Americans Love Their Living Landscape


Here is a fascinating infographic based on a survey carried out this winter by the OPEI (Outdoor Power Equipment Institute). Although the survey was done in the US, I can definitely see a very similar—if not identical—pattern here in Canada and I wonder if it doesn’t apply as well in England, Australia and other parts of the world.

I’m personally not so much a lawn guy as a garden guy, but I’m still happy to hear that green largely beats asphalt and cement in our home landscapes. Long may green reign!

20180424 ENG OPEI_American-Living-Landscape.png

There’s more information and scientific facts about living landscapes at


Rose Classification Simplified

20180423L T.Kiya, WC.jpg

With over 300 species and nearly 20,000 cultivars of roses to choose from, it’s easy to understand why it’s helpful to categorize them according to their most obvious traits. Source: T.Kiya, Wikipedia Commons

Confused about rose classification? Is that rose a hybrid tea or a floribunda? Or perhaps an old garden rose? If you’re lost, here are a few quick and easy pointers to point you in the right direction: just the right thing to bone up on before you head to the Rose Show!

Rose Classification

There is no single system of classification for garden roses. Pretty much every rose society has its own. In general, however, roses grown commercially these days are placed in one of the following categories:


20180423A Fosa glauca, Wouter Hagens, WC

If the rose’s name is written in italics, it’s probably a species rose, like this Rosa glauca. Source: T.Kiya, Wikimedia Commons

• grow spontaneously in the wild
• single flowers, scented or not
• bloom once a year
• fruits (rose hips) often ornamental
• bear species names (Rosa blanda, Rosa glauca, etc.)
• variable hardiness (1 to 10, depending on the species)


20180423B Rosa Mundi Libby norman, WC.JPG

Old garden rose ‘Rosa Mundi’. Source: Libby norman, Wikimedia Commons

• date from before 1867 (1920 according to some definitions)
• generally small to medium-size flowers, often double
• often very fragrant
• most bloom only once a year
• many subcategories: gallica roses, damask roses, moss roses, etc.
• variable hardiness (4-9, depending on cultivar)


Repeat-flowering roses, most developed after 1920. They were, through the 20th century, the most popular garden roses, but are now being replaced by the easier-to-grow shrub roses (see below). There are several categories:

A. Hybrid Tea Roses:

20180423C Rosa 'Peace', Arashiyama, WC.jpg

Hybrid tea rose ‘Peace’. Source: Arashiyama, Wikimedia Commons

• large, double, reblooming flowers with high-centered buds
• one flower per stem, rarely more
• stiffly upright habit with sparse foliage, making a fairly unattractive plant
• height: usually 3-5 ft (1 to 1.5 m)
• usually grafted
• not very hardy (zone 8); winter protection needed in most climates

B. Grandiflora Roses:

20180423D Rosa_'Queen_Elizabeth' Captain-tucker, WCJPG.JPG

Grandiflora rose ‘Queen_Elizabeth’ Source: Captain-tucker, Wikimedia Commons

• essentially a hybrid tea with 3-5 flowers per stem
• all other characteristics like hybrid tea
• not very hardy (zone 8); winter protection needed in most climates

C. Floribunda Roses:
20180423E iceberg_rose

Floribunda rose ‘Iceberg’. Source:

• smaller flowers, single or double, carried in large sprays (5 and above)
• stiff habit, but smaller, bushier and more attractive than hybrid tea
• height: around 3 feet (90 cm)
• usually grafted
• usually hardier than hybrid teas (usually zone 7, sometimes zone 6)

D. Polyantha Roses:

20180423F Rosa_'The_Fairy'_Krzysztof Ziarnek, Kenraiz, WC.jpg

Polyantha rose ‘The Fairy’. Source: rzysztof Ziarnek, Kenraiz, Wikimedia Commons

• significantly smaller flowers, borne in dense clusters
• abundant bloom most of the gardening season
• attractive habit, often spreading
• height: 30-60 cm
• usually grafted
• often fairly hardy (zones 4, 5 or 6)

E. Miniature Roses: 

20180423G Mandarin Sunblaze.

Miniature rose Mandarin Sunblaze®. Source:

• small flowers, individual or clustered
• most rebloom
• height: usually between 6 and 24 inches (15-60 cm)
• grown on their own roots (not grafted)
• often fairly hardy (zone 4 or 5)
• can be used as houseplants if given a period of cold dormancy


(includes ground cover roses, landscape roses English roses [David Austin roses], etc.)

20180423I Henry Hudson

Shrub rose ‘Henry Hudson’. Source:

• various origins
• usually robust, informal habit creating a shrub effect
• single or repeat blooming
• variable height, usually more than 2 ft (60 cm)
• grown on their on own roots (not grafted)
• often offer good disease resistance
• excellent hardiness: up to zone 2 for some


20180423J Blaze Improved

Climbing rose ‘Blaze Improved’. Source:

• long flexible canes from 8 to 20 feet (2.5 to 6 m) in length
• can be trained and tied to arbors, trellises and pergolas
• all other characteristics are highly variable; flower size, abundance, appearance, rebloom, hardiness, etc.


20180423K Roses_trees, Наталия19, WC.JPG

Tree roses. Source: Наталия19, Wikimedia Commons

• grafted onto on upright canes
• most are bush roses
• generally very tender (zone 7 or 8)
• often need to be buried in trenches for better winter survival in cold climates
• some are non-grafted, produced by selective pruning of shrub roses, and these are sometimes quite hardy (zone 5 or even 4)

There you go: the basic rose classifications you need to know. Good growing!20180423L T.Kiya, WC

Figs: Possibly Nature’s Strangest Fruit


A common fig (Ficus carica): the fruits are there, but where are the flowers? Source:

The genus Ficus (fig) includes more than 850 species in the Moraceae family and occurs naturally on all continents except Antarctica. Figs are generally tropical, but some rare species tolerate warm temperate climates, including the common fig (Ficus carica), a well-known Mediterranean fruit.

Extremely varied, the genus includes tall trees up to 40 m tall, shrubs, epiphytes, climbing plants and also the famous “strangler figs,” hemi-epiphytes that germinate on the branch of a host tree, then end up strangling it and taking its place as a forest giant. Their abundant fruits of figs are a vital element of the diet of many rainforest animals. In fact, some birds and bats feed almost exclusively on figs … and deposit fig seeds in their excrement, thus helping spread the species.

Fruits Unlike Any Other

20180422B Dinesh Valke, WC.jpg

The tiny fruits of the weeping fig (Ficus benjamina) may be tiny and hard, but they’re still figs. Source: Dinesh Valke, Wikimedia Commons

The fruits of all Ficus species are called figs, whether they are the relatively large, edible fruits of the common fig tree (F. carica) that you find fresh or dried at the market or the tiny hard fruits of your living room’s weeping fig (F. benjamina). And they’re all really very strange!

What is so odd is that fig trees never seem to bloom. With other fruits, a flower almost appears first, often covering the tree or shrub in spectacular bloom. The flower then turns into the fruit you harvest. But that’s not the case with figs. You only see small a fig that starts to form, then grows in size and eventually changes color to show the world it is ready to harvest. But there were no flowers in sight. Fruits without flowers? How is that even possible?

20180422J ENG

Fig flowers are found inside the fruit. Source:

In fact, though, the fig tree does have blooms, but the flowers are inside the small “fruit” in formation. Technically, a fig is not a simple fruit, but an inflorescence: a fleshy, hollow receptacle whose inside surface is lined with numerous tiny flowers. This type of multiple fruit is called a syconium, a word usually only seen in crossword puzzles. (For convenience’ sake, I’ll be using the term fruit instead of syconium in this text.)

20180422C Ficus benghalensis Joe Mabel,

Banyan (Ficus benghalensis) fruits. Note the small hole (ostiole) at the tip of each one. Source: Joe Mabel,

You’ll notice that there is a tiny hole at the tip of each fruit. It is through this hole (called an ostiole) that the pollinator reaches the flowers. When the fruit is ready to be pollinated, the ostiole opens marginally and the fruit emits an enticing scent containing specific pheromones to attract a female wasp of the right species.

And yes, it has to be just the right kind of wasp. Most fig species have their corresponding fig wasp. This is an example of extreme mutualism, because the fig cannot reproduce without its exclusive wasp and the wasp can only feed on its specific fig species. This is a big evolutionary risk to take, because if the fig species were to disappear, the wasp would quickly follow it into extinction and if the wasp were to be wiped out, the fig tree would have no pollinator!

20180422D JMK, WC.jpg

Fig wasp. Source: JMK, Wikimedia Commons

The tiny wasp penetrates through the ostiole*, bringing pollen from another fig tree of the correct species. While making its way through the tight hole, the female damages her antennae and her wings are shredded, but that’s all right, as she’ll never need them again. Once the female is inside, the ostiole begins to close again in order to prevent predators from taking the same route. However, often more than one female manages to work her way inside before the opening is completely plugged. When inside, the female visits the tiny flowers—there can be dozens or even hundreds of them!—inside the fruit, laying eggs on some and pollinating others. Then she dies, her role accomplished.

*In some species, the female wasp does not penetrate the fruit, but inserts its eggs from outside by means of an ovipositor, always passing through the ostiole.

Immature fig cut open, showing the fig wasps inside. Source:

The larvae hatch and consume some of the small seeds that are forming … but that’s not a problem: the fig has planned for this. It’s more than willing to sacrifice a few seeds so that the others can mature.

In most species, wingless male wasps fertilize female wasps inside the fruit and then die, never having seen the light of day. The female, now pregnant, leaves the fruit, having to cross through a cluster of fertile male flowers as it leaves and thus picks up pollen. She then flies to a young fruit of the right species at the appropriate stage of maturity. She enters the young fruit … and the cycle repeats itself.

There are a lot of variants on this cycle. In some species, for example, the male wasp does leave the fruit before fecundating the female, although, wingless as he is, he doesn’t go far. To get out, he “drills” a hole out through the side of the fruit and waits just outside. The females are then able to work their way out the hole he prepared and hopefully one will mate with him. He then dies and the female abandons him, flying off in search of a new fig to pollinate.

Are There Dead Wasps Inside Figs?

20180422E Kyle-the-hacker, WC.jpg

Mature fig: each seed is surrounded by a juicy fruit… and all the dead wasps have been absorbed. Note the ostiole, the opening that gave entrance to the female fig wasp, is still visible. Source: yle-the-hacker, Wikimedia Commons

And for those who are picky about what you eat, you can rest assured. When you eat a fig, you are not consuming the cadavers of the wasps that died inside. As it matures, the fig produces an enzyme that digests dead wasps and uses the resulting minerals for fruit development. So the fruit is perfectly bug-free by the time you eat it!

Fruits Without Pollination?

Wild figs as well as many cultivated varieties of common fig (F. carica) are pollinated by wasps as described above … but some common figs are exceptions to the rule. Many cultivars are parthenocarpic, that is, they are able to produce fruit without pollination. Since they aren’t pollinated, they don’t produce viable seeds either.

Parthenocarpic plants occur occasionally in nature, usually by mutation. As these plants either produce no seeds or infertile ones, they can’t reproduce in the wild and are quickly eliminated by natural selection.

In cultivation, though, parthenocarpic fruits are often considered desirable and are often carefully maintained for generations by humans through asexual means of propagation (cuttings, grafts, etc.). After all, who wants to have spit out banana and orange seeds? (Yes, originally bananas did produce huge and indeed, very hard seeds you had to dispose of somehow.) Or to have to grow space-hungry male persimmon trees as pollinators when a parthenocarpic female can do the job on all her own? Or to ensure the presence of pollinating wasps of just the right species in just the right place at just the right time when you could instead use parthenocarpic fig trees to produce fruit and never need worry about needing fig wasps.

20180422F Brown Turkey

‘Brown Turkey’ fig is just one of many figs that is parthenocarpic. No wasp is needed for fruit production. Source:

Indeed, the wasp that pollinates the common fig (F. carica), Blastophaga psenes, is not found everywhere fig trees are grown today. The fig tree and its wasp are native to the Mediterranean, but while it has been relatively easy to acclimatize figs trees to other areas, the wasp has been less accommodating. In cooler climates, in particular, you can often grow figs (although you may have to bury them in trenches over the winter to help them survive), but the common fig wasp simply won’t take cold winters. Fortunately, that’s not a problem, since there are many parthenocarpic varieties that don’t need pollination!

And the history of parthenocarpic figs goes back a long, long way. In the Middle East, archaeologists discovered preserved fruit from a parthenocarpic fig tree estimated to date back at least 11,200 years! That’s well before the domestication of the second-oldest crop in the sector: wheat! So humans have been growing parthenocarpic figs since the very beginning of agriculture!

Figs: their flowers may be insignificant, but their fruits are definitely full of surprises!20180422A

When Insects See Yellow




Yellow sticky traps catch harmful insects, yet pollinating insects are not drawn to them. Source:

Many harmful insects are attracted to the color yellow. It’s the color of plants under stress and millions of years of evolution have taught them to head directly to yellowing plants whose defenses are probably weakened.

You can find yellow sticky traps in most garden centers. They are simply pieces of yellow plastic or cardboard covered with a sticky, non-drying glue. Hang or clip one on or near a plant that is susceptible to infestations from flying insects (whiteflies, fungus gnats, aphids, thrips, leafminers, leafhoppers, moths, etc.)… then keep your eyes peeled. At the beginning of an infestation, you will quickly notice the presence of a lot of winged prisoners on the trap, a sign it’s time to think seriously about a pesticide treatment (insecticidal soap, neem, etc.).

And if you’re very lucky, the trap can even nip the infestation in the bud: if the very first whitefly arriving in your garden or your houseplant lands straight away on the sticky trap, it may be game over for whiteflies (or aphids or leafhoppers, etc.) for the year!

A Seed-Starters Glossary

20180420A ENG, & .jpg

You don’t understand the language used in seed catalogs? You’re not alone! Source:, &, montage

Seed and plant catalogs wing your way to your door and pop up on your screen. Garden centers are full of displays of seed packets of all kinds. It’s so exciting! You dive in and try to pick out the very best plants for your use. But the vocabulary found on the back of seed packs and in printed and virtual seed catalogs can be arcane, even confusing. For many beginners, it’s like reading a foreign language! To help you, here are a few terms you may encounter and their definitions.

Acclimatization: A vital action taken just before transplanting seedlings outdoors. It simply means to place the seedlings, still in their pots, outdoors in the shade for 2 or 3 days, then in partial shade for 2 or 3 days, then in full sun for 2 or 3 days. The seedlings are now “hardened off” and ready to transplant to their permanent location.

20180420G Twinki.jpg

Annuals grow quickly, but die after they bloom. They leave seeds to start a new generation. Illustration: Twinkl

Annual: a plant that completes its life cycle, from germinating to seed production, in one single year, then dies. Ex.: cosmos, marigold, sunflower.

Hardy Annual: an annual that tolerates cool soil and even a bit of frost. It is usually sown directly in the garden, early in the spring. Ex.: spinach, sunflower.

Half-Hardy Annual: an annual that tolerates could soil, but not frost. It is usually sown indoors in short-season or cool climates, but directly outdoors in warmer ones, as soon as there is no risk of frost. Ex.: cosmos, lettuce, petunia.

Tender annual: a plant grown as an annual that needs constant warmth and will not take frost. In all but tropical climates, it is generally started indoors and transplanted into the garden when both the soil and air have warmed up and there is no risk of frost. Ex.: basil, begonia, tomato.

Biennial: a plant that completes its life cycle in two years, usually producing a rosette of leaves the first year and flowers and seed the second. It dies after seed production. Ex.: foxglove, parsley.

Perennial: a herbaceous plant (not woody) that lives more than two years and that blooms more than once. It does not die after flowering.

Botanical Name: see Scientific Name.

Bush-type: see Non-Running.


Leaf suffering from chlorosis. Source:

Chlorosis: when leaves contain insufficient chlorophyll. They are often pale, yellow, or yellow-white. An iron deficiency, or lack of iron, is a common cause of chlorosis. See Nutrient Deficiency.

Cold Treatment (Stratification, Vernalization): subjecting to cold temperatures seeds that need to go through a cold period before germinating. Usually they are sown in pots of moist soil and placed in a refrigerator for several weeks before exposing them to heat. An alternative is to sow them outdoors in the fall in a cold climate where they will naturally undergo cold temperatures. Many perennials, shrubs, and trees from temperate climates require a cold treatment.

20180420C www.canolacouncil.or.jpg

Seedling with two cotyledons. Source: www.canolacouncil.or

Cotyledon: a seed’s first leaf, usually simple and often very different in appearance from mature leaves. Most seedlings have two cotyledons, but there are seedlings with only one cotyledon, more than 2 cotyledons and without any cotyledon.

Cross-Pollination: The transfer of pollen from the anther of a flower of one plant to the stigma of a flower of another plant of the same species. It is usually carried out by insects, birds or wind.

Cultivar: a plant raised and multiplied by humans, that does not exist in nature. Its name is typically written between single quotes (‘   ‘). The name derives from “cultivated variety.” Ex.: in Cosmos bipinnatus ‘Sonata White’, ‘Sonata White’ is the cultivar name.

Determinate: said of a tomato plant (and a few other plants) in which each branch ends in a cluster of flowers, which therefore limits its upward growth. Determinate tomatoes make fairly small plants and don’t always need staking. They tend to produce all their tomatoes at about the same time.

Indeterminate: said of a tomato plant (and a few other plants) whose flowers appear in the axils of branches and not at the stem tip. Therefore the stem continues to grow in height throughout the growing season. These tomatoes need staking or a large tomato cage. They may produce less fruit at once than a determinate tomato, but usually do so over a long harvest season and often give double or triple the yield of a determinate tomato.

Dioecious: refers to a plant whose male and female flowers are borne on different plants. The asparagus is dioecious.


Male (left) and female (right) squash flowers. Squash plants are monoecious, thus flowers of both sexes are borne on the same plant. Source:

Monoecious: refers to a plant that produces separate male flowers and female flowers on the same plant. Often the female flower is easily recognized because it has a small ovary at its base in the shape of the fruit to come. Squash, melons and cucumbers are monoecious.

Perfect Flower (Bisexual Flower, Hermaphroditic Flower): said of a flower that has both male and female organs, thus both a stigma and stamens. This is the most common situation in nature.

Direct Sowing (Direct Seeding): sowing a plant directly outdoors where it is to grow. Beans, marigolds, and corn are often direct sown.

Do not cover: said of a seed that should not be covered with soil at sowing, usually because it is either very fine or requires light to germinate, or both.

GMO: genetically modified organism. Said of a plant into which humans have inserted genetic material from another plant or even an animal without going through pollination. There is, for example, corn containing the genes of Bt (a bacterium) and varieties of canola and soybean which with inserted genes that make them resistant to herbicides. At the time of writing this, there are no GMO seeds or plants available to home gardeners.

Hardening Off: see Acclimatization.

Heirloom Vegetable (Heirloom Plant): an old variety. Some authorities consider a plant having been introduced more than 50 years ago to be an heirloom variety, others prefer the definition “before the 1940s.” Most heirloom vegetables are produced through open pollination, that is pollination carried out by insects, birds, or wind. Examples.: ‘Brandywine’ tomato, ‘Golden Bantam’ corn, etc.

Hybrid: plant resulting from the crossing of two different breeds, species or genera. F1 hybrids are the most common type of hybrid and are the result of a first-generation cross (F1 means “1st filial generation”). Usually, F1 hybrids are more robust than non-hybrid plants, but more expensive, because they have to be manually pollinated in a greenhouse setting. F2 hybrids, less common on the market, are seeds of F1 hybrids, thus the second generation (2nd filial generation). They are cheaper, as they are generally produced by natural pollination, but tend to give less reliable results than F1 hybrids.

Last Frost Date: the date used to calculate when to plant tender plants, referring to the approximate date when you can expect the last spring frost to occur. On seed packs and in seed catalogs, you’re often told to plant or sow outdoors so many weeks (6 weeks, 8 weeks, etc.) before the last frost date. You can ask a local garden club or garden center for the last frost date in your region, then simply count backwards to find the right date for sowing seeds.

Latin Name: see Scientific Name.

Nutrient Deficiency: results from the lack of a vital mineral in the soil (phosphorus, potash, nitrogen, zinc, boron, iron, etc.). It can have various symptoms include discolored or deformed leaves or slow growth. Treatment with a complete fertilizer (containing all the trace elements, such as a seaweed or fish fertilizer) will usually overcome a deficiency.

Organic: various definitions. Organic seeds are harvested from plants that have not been treated with synthetic (that is to say, chemical) pesticides or fertilizers. Organic pesticides and fertilizers are derived from natural sources, not from chemical synthesis.


Peat pots. Source:

Peat Pot: pot made of pressed peat, coir or other organic materials, usually used for seedlings that will not tolerate transplanting. The peat pot allows roots to grow right through its sides and bottom and can therefore be transplanted into the garden without removing it. The roots of the plant will then grow right through the peat pot into the surrounding soil.

Pelleted Seed, Seed Pellets: seeds covered in a product (usually clay) which facilitates their handling.

Multi-pellets: seed pellets that include several seeds and are used for plants that look best when grown in a clump, such as bedding lobelias.

Pinching: removal of a plant’s terminal bud (bud at the end of the stem). Pinching stimulates branching, giving a more compact and attractive plant, but may delay flowering. It is traditionally done by “pinching” the top growth between the thumb and forefinger, but can also be done using pruning shears or scissors.

Requires Light to Germinate: said of a seed that germinates only in presence of light, be it sunlight or artificial lighting. These seeds should be sown without covering them with soil and the pot should be placed in a brightly lit spot.

Running: said of a squash with long creeping stems that require a lot of space in the garden, like a pumpkin. This is the natural state for squash.

Non-Running (bush type): said of a squash that produces a short stem and a rosette, taking up less space in the garden than a running squash. The zucchini is the best known non-running squash.

Scarification: action of filing, nicking, or cutting a seed before sowing it. It can also involve soaking it for several hours in warm water. The goal of scarification is to penetrate very hard seeds (morning glories, hibiscus, etc.) and thus accelerate their germination.

Scientific Name (Botanical Name, Latin Name): it consists of two words, the first being the genus name (name shared with related plants, much like a human surname) and the second, the specific name, which determines the plant accurately. For example, Solanum tuberosum is the scientific name of the potato and Solanum melongena, of the eggplant. Both share the same genus name, Solanum, because they are closely related, while the specific name serves to make it clear to which type of Solanum the writer or speaker is referring. The scientific name is usually written in italics when possible.

Self-fertile: refers to a plant whose flowers can self-pollinate, that is to say that its own pollen can ensure seed production. Most plants are self-fertile.

Self-sterile: said of a plant which has to be pollinated by another variety in order to produce seeds. Many fruits (apples, pears, plums, cherries, etc.) are self-sterile or partially self-sterile. In their case, it is always best to cultivate at least two cultivars of the same species nearby, as cross-pollination is necessary for them to produce abundant fruits.

Stratification: see Cold Treatment.

Thinning: removing some seedlings or fruits in order to allow room for others to grow better. Usually this is done by cutting the excess plants or fruit stalks the base.

Transplanting: moving a plant from one place to another. In the case of seedlings, this is usually from the pot in which they were sown into a larger pot or into the ground.



Treated seed is inevitably stained bright colors to avoid any confusion with non-treated seed. Source:

Treated seed: seed has been treated with a fungicide to prevent rot in cold or wet soils. This treatment is not considered acceptable to organic gardeners.

Untreated Seed: seeds that have not been treated with fungicides and therefore acceptable in organic gardening.

Vernalization: see Cold Treatment. It can also mean subjecting growing plants to cold in order to stimulate flowering.20180420A ENG, & .jpg

Do You Really Need Leaf Shine Products?

20180419A ENG, &

Leaf shine products are widely available, but are they safe for plants? Source:, &

Sometimes when you buy a houseplant, you’ll find its leaves are particularly shiny. Now, this can be innate—the leaves of certain plants, and in particular those of schleffera (Schefflera actinophylla), zz plant (Zamioculcas zamiifolia) and mirror plant (Coprosma repens), are naturally very glossy—but often what you’ve found is a plant that was treated with leaf shine, also called leaf polish. Florists, especially, like to add value to the foliage in their floral arrangements and so spray the leaves with it. They also tend to apply it to the houseplants they sell. And leaf shine products are readily available in stores and on the Internet for you to use yourself.

So, leaf shines make leaves glossy, but are they good for plants?

Manufacturers claim they are. They say they remove dust, dirt and lime deposits, help the leaves breathe better, reduce evaporation and prevent dust from recurring. And, of course, that they “leave the foliage glossy and bright,” which is apparently a desirable thing.

And it is true that, in general, these products are not terribly harmful: your plants won’t keel over and die immediately after you apply them. However, they’re not without undesirable side effects either.

What makes things complicated is the ingredients often seem to be a company secret. It’s hard to know what they contain. And each leaf shine product is different. Some contain silicone, others different oils and waxes … and all these are products that can do some harm if not properly applied.

Cut Foliage

First though, there is no disadvantage to applying leaf shine to cut leaves, as florists do when preparing flower arrangements. The moment these leaves were harvested, their death was inevitable, usually within a week or two. To make them shine for what’s left of their life doesn’t change the eventual outcome.

Artificial Plants

Leaf shine is also recommended to remove dust and grime on plastic and silk plants and give them a “healthy sheen.” (Yes, one label actually says that!) They’re unlikely to harm fake plants and, besides, I’m a gardener. I honestly don’t care what happens to artificial plants!

Live Houseplants

The situation is much more complex in the case of living plants, especially ones you want to keep alive.

When the label states that the product helps the plant breathe better, but assures at the same time that it also reduces water loss due to transpiration, this is actually contradictory information. Plants do most of their breathing via stomata, pores that open to allow gaseous exchange (respiration), but in doing so, they also allow water to escape (evapotranspiration). Anything you do to increase a plant’s respiration will also increase transpiration … and anything you do to reduce evaporation will decrease respiration. What manufacturers are claiming is kind of a horticultural case of having your cake and eating it too.

20180419B ENG

You should limit leaf shine to the upper surface leaves of dicot plants, otherwise the product could block the stomata found mostly under the leaf and reduce respiration. Source:

Theoretically, although this is not always made clear on every product label, you should only be spraying the upper surface of the leaf with leaf shine. If you spray the underside of the leaf, where the majority of stomata usually are, it may block them and thus reduce the plant’s respiration … and by consequence, its development and even survival. On plants with stomata only on the underside of the leaf, leaf shine will not negatively affect respiration.

However, coating the upper surface with oil or wax has another undesirable effect: it reduces photosynthesis. Not a lot, but a little. Any coating shiny enough to make the leaf appear glossy also reflects light and, of course, light that is reflected is not absorbed. Essentially, spraying your plant with leaf shine is the equivalent of covering it with shade cloth.

Since lack of light is the major negative factor in maintaining plants indoors, leaf shines, although they only reduce photosynthesis to a fairly small degree, can nevertheless be harmful to plants already lacking light, slowly undermining their health.


If you read the product label (so few people do!), you’ll notice it usually recommends that you not apply leaf shine to certain plants, such as plants with fuzzy leaves, like African violets), succulents, ferns and flowering plants. Some state things the other way around and suggest using only on “houseplants with hard-surfaced leaves.”

What is not made clear, at least not on the leaf spray products I have seen, is that it is best to never apply it to monocots of any sort, because unlike dicots, most of whose stomata are on the lower surface of the leaf, in monocots, the stomata are distributed fairly evenly on both sides of the leaves. Leaf spray can seriously impinge their respiration.


Just some of the many houseplants you should avoid spraying with leaf shine. Source:, montage:

So, it’s best to not apply leaf spray to such monocots as yuccas, orchids, dracenas, bamboos, sansevierias, etc. nor any of the aroids (philodendrons, photos, monsteras, dieffenbachias, peace lilies, etc.). It is even more important to never apply it to bromeliads, especially the famous “air plants,” which absorb almost all their moisture from scales on their leaves, as leaf spray will clog the scales. Avoid applying it too to aquatic plants with floating leaves, as they only have stomata on the upper surface of the leaf.

When you start to make a list of the plants you shouldn’t really use leaf spray on, you’ll find it includes nearly two thirds of the most popular houseplants!

When Not to Spray

The small print will also likely warn you against using leaf spray:

  • In hot weather;
  • On sunny days;
  • When the leaves are wet;
  • On young shoots.

It sounds to me like they’re saying to only apply it to dormant plants … and after dark!

Homemade Leaf Shine Products

20180419F & .jpg

Coating leaves in human food products is rarely a good idea! Source: &, montage:

Do-it-yourselfers will find plenty of sites on the Web proposing homemade products to give houseplant leaves a shiny appearance: margarine, mayonnaise, olive oil and many, many more. In general, these products do make leaves shine … but the restrictions above still apply: they decrease the availability of light and harm respiration if not applied correctly. Also, homemade coatings are usually very sticky and quickly become covered with dirt, dust and pet hair. Not only are they no better for your plants than commercial products, they’re actually worse!

Giving Leaves a Natural Luster

Having gone over all this, I think it’s time to ask the real question: do you really need leaves that look lacquered?

It seems to me that the natural luster of a leaf should be enough. That a philodendron should look like a philodendron and a ficus should look like a ficus, not like they were made of patent leather!


To give leaves a “natural shine,” just clean with soapy water and rinse. Source:

To that end, all you really have to do is to clean the foliage of your houseplants from time to time to remove the dust and dirt that dull the natural brightness of the leaves. Sometimes simply hosing down the plant in the shower (or outdoors in the summer) is enough. If not, simply wipe the leaves with a soapy cloth to get rid of the grime, then rinse. Lime deposits (hard, white, crusty buildups) can be tough to remove with soap alone. Remove them by rubbing softly with a cloth soaked in a solution of 1 tablespoon of white in 1 quart (1 liter) of water.

Leaf shine products: thanks, but no thanks!20180419A ENG, &

Can Plants Really Repel Cats and Dogs?

20180418A &

In fact, cats and dogs really don’t seem to be bothered by so-called repellent plants. Read on to learn why. Source: & domobfdi.deviantart, Montage:

There are lots of blogs and articles on the Internet promoting repellent plants, plants that are supposed to keep cats and dogs away from the garden just by their smell. It’s a most interesting concept, because sometimes our furry little friends do cause a lot of damage in the garden … but do animal-repellent plants actually deliver the goods?

The idea usually promoted is that you simply have to plant repellent plants here and there throughout a flower bed or vegetable garden and then mammals (it seems to be mostly cats that people want to expel*) will then avoid the sector. It’s a concept as old as the world … and yet, positive evidence on the subject rare; I’d even say nonexistent. Many claims, little evidence? That’s not usually a good sign!

Lack of Studies

I have seen zero serious studies on the subject. Not one! There are many about essential oils derived from plants and used to repel insects, but that’s a different story entirely. I was looking for proof that planting certain plants in a garden setting would keep pets away … for an entire season, if not longer! Instead, I found lots of sites claiming this works, but offering no proof whatsoever. Most just seem to take it for granted that repellent plants work, repeating what the author has read elsewhere. On the few sites when there did seem to be some sort of proof, either positive or negative, it always seems to be purely anecdotal, like: “Well, I grow plant X in my garden and I don’t have a cat problem.” Yes, but neither do many gardeners who don’t knowingly grow repellent plants.


“Nope! No cats in my garden!” Source:

Most positive posts were from people who tried planting repellent plants as a preventive measure (there were no cats visiting their garden, but they wanted to keep them away) and they’re the first to claim victory. “I planted plant X and no cats have come, so it must have worked!” Obviously, that proves nothing. Maybe cats simply have no reason to visit that garden? Or the owner is not looking at the right time?

Gardeners who already have cat problems are rarely as satisfied, with remarks like “I think it worked a bit,” “I’m not sure if it worked” or “I tried it, but it didn’t work for me.”

Even if you turn to sites hosted by veterinarians, where you think there would be something more concrete, you find a mix of responses. Some simply list repellent plants, but offer no proof, and a few seem to take a more studied look at things and suggest that some plants might have repellent characteristics, but at short distances. Usually, 6 to 8 inches (15 to 30 cm) is the distance given. Essentially, therefore, cats and dogs would only react to repellent plants when they’re right next to them.

My Experiences

A few years ago, I tested a few of these plants on my own pets: my cat Geisha (may she rest in peace) and my dog Maggie, just for the fun of it. This was hardly a scientific study. There were no controls and—who knows?—maybe my pets are just less reactive to scented plants than others? Or trusting of me? Still, I must admit the experiences didn’t lead me to think very favorably about animal repellent plants!

The Piss-Off Plant


The famous Piss-Off Plant (Plectranthus caninus) is more likely to piss off gardeners than cats. Source:

I got into this years ago when a plant new to me came onto the market as a cat- and dog-repellent. Called by various trade names, including Scaredy Cat™, Piss-off Plant™, Dog’s Gone™ or Bunnies Gone™, it was said to be Coleus canina, It didn’t take much digging to discover its real name is Plectranthus caninus: an honest mistake, as the two plants are closely related. Its promoters claim it will keep dogs, cats and other mammals (raccoons, rabbits, etc.) at bay.

One seller even invented a detailed background for the plant, claiming it’s a hybrid developed by an Australian amateur gardener by crossing a plectranthus with a coleus, although, in fact, Plectranthus caninus has been growing wild in Africa and India for hundreds of thousands of years. Moreover, when one seller tried to get a patent for this plant (under the name Sumcol 01), the request was denied on the grounds that “the plant presented no discernible difference from the species.”

Despite its unpleasant odor, released when you brush against or stroke the plant’s sticky foliage, there is no evidence that cats, dogs or other animals are in the least disturbed by the presence of Plectranthus caninus. I added one next to Geisha’s favorite sunbathing spot and she just ignored it. In fact, she’d often lean against it when she slept. Nor did she react if I held a cut branch in front of her. I rubbed a leaf with my fingers and held them in front of her muzzle, she did pull her head back, but then, Geisha never did appreciate anyone invading her personal space.

As for Maggie (the dog), she was harder to test, being naturally more excitable, but seemed to show no special reaction when I held a branch in front of her. Placing a pot next to her water bowl didn’t dissuade her in the least, but she did sniff my fingers more willingly than Geisha after I had rubbed the leaves and didn’t seem put off.

My conclusion based in this very limited test what that Plectranthus caninus has no repellent powers whatsoever … on my pets!

The Do About Rue


Rue (Ruta graveolens) is pretty enough, but potentially harmful to humans … and doesn’t seem effective as a cat repellent.

I tested rue (Ruta graveolens) at the same time. According to popular belief, it will keep away cats away from the garden, but when I placed Geisha next to the plant growing in my flower bed, she ignored it. I put on latex gloves (rue is phototoxic to many people and should be handled with great care) and tried dangling it front of her nose as she slept. Again, no reaction. Maggie just ignored it as well.

With rue, the question you really have to ask is whether you want to risk causing grievous bodily harm to your family in a probably futile effort to keep cats away? I no longer grow rue since a friend of mine had a painful reaction after brushing against one … in my garden!



People love the smell of lavender, but cats seem indifferent to it. Source:

Humans consider the scent of lavender (Lavandula spp.) delightful, but it’s actually a natural repellent. The plant produces it to repel insect pests and grazing mammals … but the scent itself isn’t really what keeps them away: it’s the bitter compounds in the leaves that insects and certain mammals avoid. Some websites suggest that lavender will repel cats, but certainly neither of my pets minded it at all. Also, feral cats sometimes cause damage in commercial lavender fields, suggesting lavender has little effect on cats indeed.



Clearly this cat is not bothered by African marigolds (Tagetes erecta). Source:

I tested marigolds (Tagetes spp.) at a later date, because I had not heard it was supposed to have repellent effects, at least not on mammals.

Different marigolds have different scents, some attractive to people (T. lucida and T. minuta), others distinctly unpleasant (T. patula and T. erecta). These odors are all designed to repel insects, or at least, to keep them from eating the plants. You see, the plant really doesn’t want to repel insects: it needs pollinating ones to ensure its flowers are fecundated. In fact, marigolds are widely used in companion planting to attract pollinating insects. It only wants to keep insects from eating its leaves. So its taste is repellent; its scent, not so much.

Geisha and Maggie both found marigolds (I tried T. patula, T. erectato and T. minuta) be of no interest whatsoever and were neither rebuffed nor attracted by them.

And the Others


The curry plant (Helichrysum italicum) smells like curry and that doesn’t seem to bother cats. Source:

I suspect that, if any plant that has a scent, somebody somewhere will eventually claim it repels cats (and maybe dogs). Here are some other plants that have that reputation, but didn’t work on my pets: curry plant (Helichrysum italicum), rosemary (Rosmarinus officinalis) and pennyroyal (Mentha pulegium). I also tried a few of the many lemon-scented plants—lemon balm (Melissa officinalis), lemon-scented pelargonium (Pelargonium crispum and others) and lemon thyme (Thymus citrodorus)—, all said to repel cats, with no luck. I stopped testing after Geisha died, as we no longer have a cat to use as a test subject. (My wife has developed a serious cat allergy, so Geisha was not replaced.)

How Believers Can Use Repellent Plants

If you still believe that plants have a significant repellent effect on cats and dogs, calculate their effect is limited to a distance of 6 to 8 inches (15 to 20 cm) from the plant. Therefore, the method most often recommended, that is, planting them here and there among garden plants you want to protect, is simply not going to work. Any repellent effect would be too diluted and cats would simply have to wander around the individual repellent plants to get their favorite spot.


For a repellent plant (here, Lavandula angustifolia) to be effective, you’d really need to use it as a barrier plant. Source:

Other sites suggest a more likely method: using them as barrier plants, that is, surrounding the zone with dense plantings felines can’t find a way around. One site recommends using taller repellent plants as being more effective, as cats simply jump right over short ones.

Personally, the cats and dogs in my neighborhood never bother my garden, so I have no need for any kind of pet repellent. If I did, given the results of my experiments, you can be sure I’d try something other than repellent plants!

Read Keep Cats Out of Your Gardenfor a few methods that really work!20180418A &