5 Plants With Weird Foliage

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There is fascinating foliage all around if you just make the effort to look! Source: Clipart Library

The whole point of a leaf is to collect sunlight and convert it via photosynthesis into sugars for the plant’s growth. Thus, a leaf simply has to be green to be functional. You’d think a simple flat shape would be enough, but no. There are as many leaf shapes as there are plants and they come in far more colors than they legitimately should. Here are some of the more interesting and memorable ones.

Swiss Cheese Plant (Monstera deliciosa)

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The Swiss Cheese plant has slits and holes much like Swiss cheese. Source: Forest & Kim Starr, Wikimedia Commons

This is a very common houseplant whose leaves just keep getting bigger and bigger … and weirder and weirder. If you’ve ever grown one from a young plant, you know the first leaves are entire and heart-shaped (the Swiss cheese plant is often mistaken for a philodendron at this point). Then, as it grows, the leaves get larger and splits start to appear. As the leaf increases in size, the number of splits increases and then holes (leaf perforations) start to show up. The leaf keeps increasing in size and, as it does so, more and more perforations appear. If you have the space for this huge plant (they don’t call it Monstera for nothing!), the leaves can reach nearly 1 meter (3 feet across) and will be strikingly beautiful … and weird.

As for why the leaves become so “tattered” (and I use that word in the nicest possible way), that’s a matter of conjecture, but I like the theory that it’s because large leaves are like a banner strung across a street: if you don’t punch a few holes in them, the wind will tear them. I’ll write more about this phenomenon in a future blog.

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The inflorescence of the Swiss cheese plant is spectacular, but rarely seen except on very mature specimens. Source: Karl Wimmi, Wikimedia Commons

The Swiss cheese plant is normally a climber and will grow best when offered a (sturdy) moss stake to cling to. It tolerates low light, but for big leaves, give it as much light as you can. This will also keep it more compact. You are allowed to cut off the numerous aerial roots it produces (I like to keep a few for show). It may even bloom for you one day, with sail-like white blooms (think of a Spathiphyllum). The fruit that follows is edible when it fully ripens and its scales start to drop off and, as the name Monstera deliciosa suggests, is sugary sweet. Other than the ripe fruit, though, the plant is poisonous.

The Swiss cheese plant is easy to grow indoors, but does appreciate good atmospheric humidity (to prevent leaf browning). Otherwise, just give it regular houseplant care … and be patient!

Cooper’s Haworthia (Haworthia cooperi)

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Haworthia cooperi’s window leaves can appear completely otherworldly. This is H. cooperi truncata, with rounded leaf tips. Other varieties have pointed tips. Source: 9gag.com

I’m using this plant as an example of a window plant. There are many others in such genera as Haworthia, Lithops, Peperomia, Senecio, Fenestraria and Frithia, but all have the same fascinating characteristic: they have a translucent area at the leaf tip where sunlight can reach down through the gelatinous transparent leaf interior and reach the photosynthetic cells along the outside edges lower down. This is exactly the opposite to how other plants function. Their photosynthetic cells are located near the outside of the leaf, not buried deep inside.

Most of these window plants come from very arid climates and essentially live underground, with only their leaf tips exposed, each acting like a skylight, allowing even the buried leaf parts to photosynthesis. When we grow window plants in pots, however, sometimes we grow the plant with the entire leaf exposed, partly to show off the leaf … and partly to prevent rot.

Window plants are yet another subject I’ll cover in more detail in a future blog, but for the moment, here’s what you need to know about Cooper’s haworthia.

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Haworthia cooperi cooperi has pointed leaf tips… but the same windows as other varieties. Source: Abu Shawka, Wikimedia Commons

It’s a small, easy-to-grow succulent that will do well on almost any fairly sunny windowsill. It produces offsets and slowly the original rosette fills in the surface of the pot with the new growths. Just grow it like any other succulent, watering only when the soil is quite dry, and you’ll have success. It will even bloom quite readily, although the flowers aren’t very showy.

To best appreciate the transparent beauty of the leaves, you do need to place this plant carefully: at about eye level, with the sun in the background. When looked down on from above, the windows are not as noticeable.

You’ll find it, or other window haworthias, in most garden centers.

Venus Flytrap (Dionaea muscipula)

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The traps of Venus flytrap lie on their moss bed, awaiting the visit of a spider or insects. Source: Mokkie, Wikimedia Commons

There is no denying the plant has weird leaves. Weird in appearance and weird in how they’re used. A broad, winged, often heart-shaped petiole rises from a small rosette and it carries on normal photosynthesis, while the leaf blade itself forms two lobes, each with a ring of teeth around the outside. When an insect or other arthropod triggers the mechanism by touching the small hairs in the center of the leaf, the leaves close quickly, trapping the creature, then the leaves produce gastric juices to digest it. Yes, this plant is carnivorous, or, to be more precise, insectivorous.

Like most insectivorous plants, the Venus flytrap developed its feeding habits because it normally grows in a very sterile environment, in this case, nitrogen- and phosphorous-poor bogs in North and South Carolina. It needs insect “meat” to supplement its meager diet.

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Remove the plastic container the plant is sold in and grow it in a sunny window sitting in a saucer of rainwater. Source: www.carnivorousplants.org

Although widely sold as a houseplant, the Venus flytrap is more of a curiosity than a good indoor plant, nor will it thrive outdoors under garden conditions unless you can recreate the environment of a cold, but nearly frost-free bog (zoned 7 to 9).

In most cases, it’s best to think of this plant as a temporary one, something to be tossed when you’re finished with it.

You can keep a Venus flytrap growing for years, though, if you know what to do and are willing to bow to its whims. Read more about it in No Hamburger for the Venus Flytrap.

Mother and Daughter Croton (Codiaeum variegatum forma appendiculatum)

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Actually, with their amazing colours and strange shapes, all croton leaves are quite weird. Source: www.pahls.com

I suppose all crotons have weird leaves. Almost always variegated, they come in a wide range of colors (red, orange, yellow, purple, green and white), plus they change colors as they mature, so leaves from different parts of the plant may be very different colors. The leaf shape too is extremely variable, from ovate to linear and entire to deeply lobed, and often twisted or spiraled.

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Certainly the oddest of all crotons thanks to its leaf extensions is the mother and daughter croton. Here, the cultivar ‘Appendiculatum’. Source: www.thepaddocks.de

But the weirdest of all the crotons are those so-called called mother and daughter crotons: C. variegatum forma appendiculatum. In these, the leaf, often fairly linear, produces a narrow stalk from its tip, then a smaller leaflet, often curiously funnel-shaped, appears at the extremity. It looks like a kite on the end of a string!

I sometimes get letters from readers who think a baby plant is growing from the tip of a mother leaf. Sorry, but no dice: the croton is just not one of the plants you can grow from a leaf cutting, even less from a leaf section. You’ll need to take stem cuttings (or air layer the plant) to multiply it.

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Croton ‘Interruptum’. Source: piergrossi.squarespace.com

There are only a few cultivars with the appendiculatum habit, one being called just that: ‘Appendiculatum’. It has green leaves, although there is also a red form bearing the same cultivar name. The other often seen is ‘Interruptum’, with green leaves mottled yellow turning into red leaves mottled orange. Never is a very common plant. Unless you have a croton nursery in your neighborhood or can order one by mail, you’ll just have to wait until one of these curious mother and daughter crotons shows up in a garden center near you.

The croton has the reputation of being a persnickety houseplant, but I have specimens over 20 years old and they do just fine. Of course, I lost more than a few until I figured out that what they really need is high humidity until they settle in. Ideally, buy them in late spring or summer, when the air is naturally humid, and put them in their permanent spot, which needs to be a brightly lit one. By the time the dry air of fall arrives, they’ll have had time to adapt to your conditions and should do fine. Other than that, basic houseplant care is all they need … but do keep them out of cold air (less than 60˚ F/15˚ C).

Crotons also make great outdoor shrubs and even hedges, but only in truly tropical climates (zones 10 to 12).

Ginkgo (Ginkgo biloba)

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Ginkgo leaves are totally original: you can never mistake them from anything else! Source: www.edenproject.com

Most really weird leaves are found on tropical plants, which is normal considering the vast majority of plants on this planet are of tropical origin, but there are still many leaf oddities among hardy plants and I think the ginkgo clearly merits a spot in the list of weird leaves.

Maybe you’ve seen ginkgoes around you so often they’ve come to seem quite ordinary to you, but their leaf shape is in fact unique among seed plants. Only maidenhair ferns (Adiantum spp.) have leaflets anything like them.

Each leaf has a very special fan-shaped form, caused by veins that split in two, then split in two again and again. It’s as if the needle of a pine started out narrow, then became increasingly crested from the mid-point on. And ginkgoes are indeed gymnosperms, closer relatives to conifers than to flowering plants, in spite of their broad leaves and deciduous habit.

250 million years ago, ginkgoes were the dominant trees on our planet and were apparently a major food source for dinosaurs. There is only one species left, G. biloba, rarely found in the wild and even then only in isolated areas of Southwestern China. However, it is now grown as a cultivated plant the world over in hardiness zones 4 to 9.

The ginkgo is a very slow-growing but forgiving tree, adapting to just about every condition as long as drainage is good.

More Weird Leaves to Come

20171130A Clipart Library.jpgI’ve only scratched the surface of plants with weird leaves. I have many others I want to present to you and hope to do so over the coming months. Also, I’m looking for suggestions. Maybe I’ll be able to include your choice in one of the future blogs! If you allow me to use one of your photos, I’ll add that too! Just write me at horticom@horticom.ca.

Do note I’m looking for plants that repeatedly produce odd leaves, nor for a single mutant leaf on an otherwise normal plant, nor do leaf oddities provoked by insects or diseases count (although I have to admit some leaf galls are pretty amazing!). Also, for the moment, I’m sticking to leaves, not weird growth habits or weird flowers.

Thanks for any help you can offer!

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In Praise of Tall Trees

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This is what the suburbs used to look like: modern developments however are sadly lacking in big trees. Photo: Fgrammen, Wikimedia Commons

An important element of residential landscaping seems to be going the way of the dodo in modern cities. Tall trees — the big, majestic ones that gave the landscape its character — are increasingly being left out in favor of smaller trees or even shrubs grafted on short trunks.

This is a fairly recent trend. If you look suburban developments over 60 years old, tall tree species dominate. Big maples and huge majestic oaks are everywhere. They helped create an atmosphere of tranquility and well-being. Take a walk in a neighborhood 40 years old or less, though, and you mostly see green lawns and shrubs, maybe a flower bed or two, and a few smaller trees you couldn’t even fit a lawn chair under, but not many larger ones. True enough, a somewhat sparse landscape can be still attractive, but it tends be so in a cold and impersonal way. Such neighborhoods aren’t really inviting. It’s as if the residents planned all along to leave their dreary home landscape on weekends for a break at the cottage … surrounded by tall trees, of course!

Just Don’t Think About It, Plant Them!

Why do larger trees deserve a place in suburban and urban lots?

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Taller trees create a homey, friendly, inviting atmosphere. Photo: Bridan Stansberry, Wikimedia Commons

First, for the shade they offer. Gardeners may complain you can’t grow anything under big trees (actually, you most certainly can: I’ve written an entire book about shade gardening, so I know it’s far from impossible!), but the fact is we’re attracted by shade. During the dog days of summer, a neighborhood well decorated with broad, shade-producing trees is livable; one denuded of any tall vegetation simply is not.

Also, human beings, by their very nature, seem to need trees in their surroundings. Is this a reminder of the long distant past when our ancestors took refuge in trees when they were attacked by predators? No one knows. Still, the feeling of peace and security that emerges from a big tree seems very real. In fact, it can be seen in different cultures all over the world: when people are given a choice of where they would like to live, they inevitably prefer not a forest, but a landscape dotted with mature, tall trees.

Of course, maybe you do feel you have trees on your property. But can you really call a small weeping tree barely 10 feet (3 m) high a tree? Or a flowering crabapple or a Japanese lilac or one of the many other “small trees” so heavily planted these days? They may be trees by definition, but you can’t walk under them without bumping your head, you can’t fit a lawn chair underneath them without your legs sticking out in the hot sun and they don’t create the atmosphere of permanence and security that large trees can provide.

How to Use Trees Wisely

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Bravo: this modern homeowner has included one tree that will reach a reasonable size. But look at the photo: wouldn’t it be more attractive with at least one tall tree reaching up from the back yard as well?

Ideally, to recreate the sense of peace and permanence you want, you’d need at least one large tree per yard. Preferably two, in fact, on in the front and one out back. Obviously, the larger the lot, the more trees it needs.

In addition to the atmosphere they create, big trees offer other advantages:

  • Reduced cooling costs in the summer;
  • Reduced heating costs in winter;
  • Minimal maintenance;
  • Increased land value;
  • An environment healthier for human physical and mental well-being;
  • An inviting landscape for our feathered friends;
  • And much more.

Trees have certain disadvantages, of course, but these are generally easy to overcome.

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Planting a tree takes a bit of effort. Photo: Maryland GovPics, Flickr

Planting them, for example, is fairly arduous … but at least you only have to do it once!

The shade they produce will reduce the choice of plants that will grow underneath, but there is still a good choice of shade plants. Where it’s too shady for a dense lawn, for example, there are dozens of equally dense, maintenance-free groundcovers.

Some trees do produce seeds or fruits that can be briefly annoying when they fall, but there are many cultivars that are either sterile or male (male trees produce no seeds).

Finally, there will be leaves to rake up each fall — yes, even so-called evergreens tend to lose leaves at that season —, but fortunately that’s only a once-a-year thing … much less work than maintaining a lawn, which usually requires weekly mowing.

Plant Tall Trees Where They Can Reach Their Full Size

When planning to buy a tree, ask about its maximum height and spread and use that info to find a suitable location. For example, don’t plant it where it can interfere with overhanging wires, too close to the house, or directly in front of a window. Nor should it reach over into a neighbor’s lot, otherwise there is a serious possibility of conflict.

Lots of choice!

What follows are some suggestions of tall trees (over 30 feet/9 m) that can decorate your property. All are low- to no-maintenance trees that will enhance your property’s value.

Note that the trees shown here were chosen for a cold climate region. In areas with more temperate or even warm climate, you’ll have an even greater choice. Measurements are averages reached under normal growing conditions.

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Red maple in its fall glory. Photo: Famartin

Red maple (A. rubrum): Long neglected by arborists, this North American native is becoming more popular, especially in colder climates. Its bark, smooth and pale gray in its youth, becomes rough over time. Its three-lobed leaves turn bright red in autumn. Prefers moist growing conditions. Height: 60 feet (18 m). Spread: 50 feet (15 m). Hardiness zone: 3b. There are also smaller, more symmetrical selections, such as ‘Morgan’ (50 x 50 feet/15 x 15 m) and ‘Red Sunset’ (30 feet x 20 feet/9 x 6 m). ‘Autumn Flame’ (35 x 20 feet/11 x 9 m) is the best choice for colder climates (zone 3).

Freeman Maple (A. x freemanii): This hybrid maple results from a cross between red maple and silver maple (A. saccharinum), but is closer to red maple in overall habit. It’s perhaps even superior to red maple as a city tree and is even a bit hardier: zone 3. There are several cultivars, including Autumn Blaze (‘Jeffersred’), 50 x 30 feet/15 x 9 m), which turns fiery red in the fall.

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The orange-red fall color of the sugar maple. James St. John, Flickr

Sugar maple (Acer saccharum): It used to be that arborists shunned this North American native, considering it unsuited to urban areas, and recommending Norway maple (A. platanoides) instead. Nowadays, attitudes have changed and that there are few situations where a sugar maple wouldn’t be considered a better choice than its Norwegian relative. Planted in isolation, it takes on a beautiful speading, rounded shape quite unlike its fairly scrawny appearance in forested areas. With its excellent orange-red fall color, it’s also much more colorful than Norway maple and less subject to winter damage. Plus its smaller, rapidly decomposing leaves have less tendency to choke out grass. Finally, it isn’t subject to tar spot disease, this disease which turns the leaves of Norway maple into an unsightly mess. Both, however, do have dense and shallow roots: there’s no denying that maintaining a perfect lawn under either maple is a challenge, though. Height: 60 ft (18 m). Spread: 40 feet (12 m). Hardiness zone: Zone 4. There are several horticultural selections, including ‘Green Mountain’ and ‘Legacy’, which offer a more regular habit on a somewhat smaller tree than seed-grown sugar maples.

Common Hackberry (Celtis occidentalis): This North American tree looks a bit like an elm but with a more rounded crown. Corklike bark. Yellow color in autumn. Height: 65 feet (20 m). Spread: 50 feet (15 m). Hardiness zone: 4.

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Ginkgo starting to take on its fall color. Photo: Crusier, Wikimedia Commons

Ginkgo (Ginkgo biloba): Very slow growing, but totally resistant to insects and diseases. Attractive yellow foliage in the fall. Always ask for a male specimen: the females drop messy, stinky fruits. Height: 45 feet (14 m). Spread: up to 40 feet (12 m), but much narrower than wide for the first 60 years or so. Hardiness zone: 4.

Honey Locust (Gleditsia triacanthos inermis): Tree with an open, often irregular crown that lets sun through. Rough bark. The compound leaves are composed of leaflets so small that they decompose quickly: you don’t even have to rake them up in the fall! The extremities of the branches often freeze during the winter in colder climates, but that doesn’t really affect its appearance. Look for the cultivars ‘Moraine’ and ‘Skyline’, as several honey locusts, like ‘Sunburst’, are too small to make good shade trees. Height: 65 feet (20 m). Spread: 55 feet/17 m. Hardiness zone: 4b. ‘Northern Acclaim’ is an extra-hardy variety: zone 3.

Amur Cork Tree (Phellodendron amurense): Little known, but very attractive and virtually without cultural problems. The bark on mature specimens is very corklike. Height: 40 feet (12 m). Spread: 40 feet (12 m). Hardiness zone: 3.

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Siberian pear is an easy-to-grow, heavily blooming tree well worth discovering. Photo: Sten Porse,  Wikimedia Commons

Siberian Pear (Pyrus ussuriensis): A large tree that dwarfs its smaller fruit tree cousins: apples, plums, cherries, etc. It’s also essentially immune to most of the diseases and insects afflicting fruit trees. It blooms abundantly in spring, covering itself with white blossoms, but its tiny fruits are of no interest to humans, although they do attract birds and small mammals. It will only bear fruit if there are two different clones in the area, since cross-pollination is obligatory for this species. Height: 40 feet (12 m). Spread: 33 feet (10 m). Hardiness zone: 3.

Oaks (Quercus spp.): A large group of trees, most tall and spreading, generally with toothed leaves. They’re considered among the most majestic of trees, but their growth is fairly slow, at least after the first 10 years or so. Height: 65 feet (20 m). Spread: 50 ft (15 m). Hardiness zone: generally, zone 4. Red oaks (Q. rubra) and scarlet oaks (Q. coccinea) are particularly interesting for their massive shape and fall color. Where space is limited, consider columnar English oak (Q. robur ‘Fastigiata’) which reaches the same height as the other oaks but rarely exceeds 13 feet (4 m) in diameter. The best oak for cold climates is bur oak (Q. macrocarpa), hardier than the others: zone 3. Shingle oak (Quercus imbricaria) is unusual among hardy oaks in that it has narrow untoothed leaves.

Think-Twice Trees

The following trees may be useful in some cases … but have problems that can seriously reduce their usefulness under certain circumstances. It’s up to you to decide whether they are worth growing under your conditions!

Horse Chestnuts, Hickories, Walnuts (Aesculus spp,. Carya spp., Juglans spp.): They make beautiful trees, but their large fruits can be an annoyance, especially near roads. In addition, walnut trees are allelopathic (toxic to plants that grow at their base).

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River birch

Birch (Betula spp.): Most make very nice trees, with attractive bark, but they’re often short-lived (especially silver birch [Betula pendula] and its varieties) and rarely make it to their full size. In addition, they are susceptible to a wide range of diseases and insects and that can mean a lot of spraying … under some circumstances. Ask a local arborist their opinion, as the problems tend to vary greatly, from minor to major, depending on local conditions. One exception is river birch (B. nigra), especially the cultivar Heritage (‘Cully’), with bark that exfoliates gracefully: it’s long-lived and disease- and insect-free under most conditions. Height: 50 feet (15 m). Spread: 35 feet (10 m). Hardiness zone: 3.

Catalpa (Catalpa spp.): Although catalpas survive in cold regions and thus some nurserymen rate them as zone 4 trees, in fact, they tend to suffer severe winter damage in zones 4 and 5, at least periodically, and, as a result, grow very irregularly. With their abundant white to lavender blooms, they make an excellent choice in areas 6 and up, though. Height: 50 feet (15 m). Spread: 30 feet (9 m).

Linden (Tilia spp.): Tree with a strong trunk and heart-shaped leaves, plus highly scented flowers. The little-leaved linden (T. cordata) is very popular and offers many interesting cultivars, however … this genus is not a good choice in regions infested with Japanese beetles, as they literally defoliate the tree every summer. Height: 100 feet (30 m). Spread: 80 feet (25 m). Hardiness zone: 3.

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Ulmus x ‘Morton’ Accolade is a hybrid elm the looks like an American elm, but is resistant to Dutch elm disease. Photo: Bruce Marlin

Elm (Ulmus spp.): American elm (U. americana) almost inevitably falls victim to Dutch elm disease, which is difficult and expensive to fight. There are, however, several elms, including hybrid varieties, which share the American elm’s majestic upright spreading habit while showing good resistance to the disease. Before buying an elm, always ask if it’s resistant to Dutch elm disease. The Siberian elm (U. pumila) is resistant to Dutch elm disease, but is a weak-wooded tree with a poor growth habit and susceptibility to other diseases. Plus it self-seeds excessively and is considered an invasive species in many areas.

Trees to Avoid at All Costs

Ash (Fraxinus spp.): The arrival of the emerald ash borer (Agrilus planipennis), a deadly tree-piercing insect, in North America—and even now in Europe—has killed pretty much any interest in this formerly popular street tree. You might want to maintain the ones you have, but it’s probably wise to avoid planting new specimens.

Poplars, Willows, Silver Maple (Populus spp., Salix spp., Acer saccarhinum): The roots of these fast-growing trees are extremely invasive and often cause damage to domestic and municipal water and sewage pipes. They often also sucker extensively or self-sow and so become very invasive. It’s illegal to plant these trees in most municipalities.


There you go: a list of big and beautiful trees you might want to consider growing. And don’t delay, as it will take a few years before you can savor their full effect on your property!20170528B Fgrammen, WC

The Ideal Tree for Commemorating a Birth

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This ginkgo is over 100 years old.

In some families, there is a long tradition of planting a tree at the birth or adoption of a child. If not, why not start one? That way, 15, 30 or 60 years later, the child, now an adult, will always have “their” tree.

But what tree should you plant?

Where it will grow (hardiness zones 3 to 8), the ginkgo (Ginkgo biloba) is perhaps the best choice. Its growth is slow but steady, it thrives in almost any well-drained soil, it is resistant to insects and diseases and, especially, it lives a long, long time: 1000 years or even more. So even if the newborn lives to be over 100 years old, their commemorative tree will always be there to remind them of their family.