Keep Your Indoor Rosemary Happy


You need to give rosemary special conditions to keep it happy indoors. Source:

Rosemary (Rosmarinus officinalis) is a popular cooking herb often grown in home gardens. It’s a half-hardy shrub and will grow outdoors year round in zones USDA 8 to 10, sometimes even in zone 7 (the cultivar ‘Arp’ is said to be hardysometimes!in zone 6). Still, gardeners in cold climates like mine have to bring it indoors for the winter … and often find it difficult to maintain.

That’s because rosemary comes from a Mediterranean climate, where summers are hot and dry and winters cool and rainy. It suffers greatly from the heat we maintain in our homes in winter. The more your conditions are like those of its place of origin, though, the better it will perform. Try moving it to that rarest of indoor locations: a cool yet brightly lit room. Night temperatures from about 38 to 50˚ F (3 to 10˚ C) are best, but 60˚ F (15˚ C) is acceptable and it can take a few degrees of frost in a pinch. If you can’t give it full sun in this frigid spot, consider adding artificial light.

Overwatering can be a problem in such a cool spot. The plant will use less water than normal and evaporation will be reduced, so you’ll probably find you’ll only need to water every 2 to 3 weeks. That does not mean to let it dry out completely, though! Continue standard watering: a good soaking when the soil is dry to the touch. It’s just that dry to the touch” will occur less frequently than in a heated room.

Only January, Yet Already Time to Sow Seeds?



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It’s only January! Surely it’s too soon to sow seeds? Source:, & mzayat. com

The new year has barely begun, yet now and over the coming month it’s already time to start certain seeds indoors.

This is a very select group of especially slow-to-mature plants. January is far too early for most seeds (think March or April instead), but you need about four to five months of indoor culture to bring the following plants to the right state of growth for outdoor planting.

  1. Agastache (Agastache foeniculum)
  2. Datura (Datura metel)
  3. Fairy Snapdragon (Chaenorrhinum origanifolium, syn. glaerosum)
  4. Lisianthus (Eustoma grandiflora)
  5. Spike dracaena or cabbage palm (Cordyline australis, syn. indivisa)
  6. Tritome (Kniphofia )
  7. Tuberous Begonia (Begonia × tuberhybrida)

No Easy Feat!


Artificial light is almost essential for seeds started in January. Source: laidbackgardener. blog

Starting seed in January in the Northern Hemisphere is not simple. The days are short, the sun is weak and, in many areas, the weather is gray more often than sunny, meaning light is seriously lacking. Also, temperatures in front of the average windowsill are cool, yet almost all seeds need warmth—and fairly even temperatures—to germinate well. As a result, you pretty much have to start these under artificial lights, such as fluorescent or LED plant lights, and in the warmest part of your home.


Germinate the seedlings under glass, possibly over a heating pad, as above. Source:

Always start winter-sown seeds “under glass” (under some sort of transparent covering) to maintain high humidity and stable temperatures and in a room that is at least moderately warm (72 to 75˚ F/21 to 24˚ C) or place the seed containers on a heating pad (one specifically designed for plants). Use a timer to set the day length of your lamp at 14 hours to simulate the long days of summer and place the containers of freshly sown seeds about 6 to 12 inches (15 to 30 cm) below the lamp. Now, wait patiently for germination to occur. (One reason that certain seeds need early sowing is that they are slow to germinate.)

Seeds That Require a Cold Treatment


Many tree, shrub and perennial seeds need a cold treatment before they will germinate. Source: laidbackgardener. blog

January (or December or February) is also a good time to start seeds that need a cold treatment (cold stratification) to germinate well. This group includes most trees and shrubs from cold and temperate climates, but also many perennials and even a few annuals.

These seeds will not germinate until they have received a given number of days of cool, moist conditions, from as little as one or two weeks to four months or more, information you would (hopefully) find on the seed pack.

The number of weeks given is the minimum requirement for that species, but there is no maximum. So, if you keep seeds that need, say, a two-week treatment in the cold for two months, that’s not a problem. That’s nice to know, because the information on the minimum cold treatment for seed X is not always available, especially for seed you harvested yourself. If you don’t know, I suggest giving seeds of perennials a six to eight-week cold treatment: that’s usually enough. For trees and shrubs, I’d recommend three months.

Simply sow these seeds in a container as you would any other, then seal them inside a clear plastic bag and pop them into the refrigerator or cold room for at least the minimum number of weeks. Afterwards, move them to a warm, well-lit spot, on a windowsill or under lights, for germination to start.

100 Seeds That Need a Cold Treatment

Here are 100 plants that germinate best with a cold treatment (there are thousands of others!). Check the seed envelope or the seed supplier’s web site for more information.

  1. Abies (fir)
  2. Acer (maple, mosts species)
  3. Aconitum (aconite)
  4. Alchemilla (lady’s mantle)
  5. Allium (ornemental onion)
  6. Amelanchier (serviceberry)
  7. Aquilegia (columbine)
  8. Asclepias (milkweed, some species)
  9. Astrantia (masterwort)
  10. Baptisia (false indigo)
  11. Buddleia (butterfly bush)
  12. Caltha (marsh marigold)
  13. Caryopteris (bluebeard)
  14. Cercis canadensis (redbud)
  15. Chelone (turtlehead)
  16. Cimicifuga (bugbane)
  17. Clematis (clematis)
  18. Cornus (dogwood)
  19. Corydalis (fumitory)
  20. Delphinium (delphinium)
  21. Dicentra spectabilis, now Lamprocapnos spectabilis (bleeding heart)
  22. Dictamnus (gas plant)
  23. Dodecatheon (shooting star)
  24. Echinacea (purple coneflower)
  25. Eremurus (foxtail lily)
  26. Eryngium (sea holly)
  27. Eupatorium (Joe Pye weed)
  28. Filipendula (meadowsweet)
  29. Forsythia (forsythia)
  30. Fragaria (strawberry)
  31. Fuchsia (fuchsia)
  32. Gentiana (gentian)
  33. Geranium (perennial geranium, cranesbill)
  34. Goniolimon (German statice)
  35. Helianthemum (rock rose)
  36. Helianthus (perennial sunflower)
  37. Heliopsis (false sunflower)
  38. Helleborus (Christmas rose)
  39. Hemerocallis (daylily)
  40. Heuchera (coral bells)
  41. Hibiscus moscheutos (perennial hibiscus)
  42. Hypericum (St. John’s wort)
  43. Iberis (perennial candytuft)
  44. Ilex* (holly)
  45. Incarvillea (hardy gloxinia)
  46. Iris (iris, many species)
  47. Kirengeshoma (waxbells)
  48. Knautia (knautia)
  49. Lathyrus (perennial sweet pea)
  50. Lavandula (lavender)
  51. Leontopodium (edelweiss)
  52. Lobelia (hardy lobelia)
  53. Lonicera (honeysuckle)
  54. Macleaya (plume poppy)
  55. Magnolia* (magnolia)
  56. Malus (apple, crabapple)
  57. Mazus (creeping mazus)
  58. Mertensia (Virginia bluebells)
  59. Muscari (grape hyacinth)
  60. Myrrhis odorata (sweet cicely)
  61. Nepeta (catmint)
  62. Oenothera (evening Primrose)
  63. Opuntia* (beavertail cactus)
  64. Paeonia* (pivoine)
  65. Penstemon (beard-tongue)
  66. Persicaria (fleeceflower)
  67. Persicaria orientalis, syn. Polygonum orientale (kiss-me-over-the-garden-gate)
  68. Phlox (phlox)
  69. Physalis (Chinese lantern)
  70. Picea (spruce)
  71. Platycodon (balloon flower)
  72. Primula (primrose)
  73. Pulsatilla (pasque flower)
  74. Quercus (red and black oaks)
  75. Ranunculus (buttercup)
  76. Ratibida (prairie coneflower)
  77. Rosa (rose)
  78. Rudbeckia (black-eyed Susan)
  79. Sambucus (elderberry)
  80. Sanguinaria (bloodroot)
  81. Sanguisorba (burnet)
  82. Saponaria (soapwort)
  83. Saxifraga (saxifrage)
  84. Scabiosa (pincushion flower)
  85. Sedum (stonecrop)
  86. Sempervivum (houseleek)
  87. Sidalcea (prairie mallow)
  88. Staphylea* (bladdernut)
  89. Stokesia (Stokes’ aster)
  90. Syringa (lilac)
  91. Thalictrum (meadow-rue)
  92. Tiarella (foamflower)
  93. Tricyrtis (toad-lily)
  94. Trillium* (trillium)
  95. Trollius (globeflower)
  96. Tsuga (hemlock)
  97. Vernonia (ironweed)
  98. Veronica (speedwell)
  99. Viola (violets)
  100. Vitis (grape, some species)
*Some species in this genus require a double cold stratification: that is, two cold treatments separated by warm one, to germinate well. Try two to three months of cold followed by two months of warmth, then again two to three months of cold. When you expose them to warmth after these repeated treatments, most will germinate quite readily.

Good growing!20180103 ENG, &

Bush Rose Hardiness: Little White Lies


20140409OBe careful when you buy a bush rose, that is, a hybrid tea, a grandiflora or a floribunda rose (as opposed to a shrub rose). The label is not telling the truth about the plant’s hardiness: it’s a sort of horticultural little white lie. And if you don’t know this, you can find yourself, horticulturally speaking, screwed.

You’ll find these roses labelled as being adapted to hardiness zone 5, or maybe even hardiness zone 4, which seems to make them great choices for the northern half of the US and also southern Canada. In actual fact, though, they are no where near hardy in either zone, but most likely only to zone 7 or even 8. In other words, forget their surviving in Boston or Minneapolis: they’ll freeze to death in the winter in most areas north of the Mason-Dixon line. Why this blatant lie?


Winter protection is required for most bush roses.

It occurs because nurseries assume you already know these roses are not hardy enough to survive on their own, that you are aware they need protection in almost any climate where prolonged winter temperatures below freezing are expected. Their zone 5 or zone 4 label is meant to give you an idea of what the plants can take if they are carefully protected for the winter. You’re expected to know that means, for example, abundant mounding if you garden in zone 6, a rose cone filled with mulch in zone 5 or even digging a trench and burying the plant for the winter if you’re in zone 4. And the same nurserymen assumes you know that a hard winter will probably kill these roses even with a good protection. Yes, they’re really that tender!

But this isn’t the 1950s when the average family had just moved from the farm to a suburban lot and brought lots of gardening experience with them. Those new suburban gardeners knew roses needed protection, plus they expected gardening to be hard work (that sort of a negative attitude towards gardening is slowly dissipating today), so didn’t think twice about the added trouble of plants needing winter protection.

Some 60 years later, that old gardening knowledge has often been lost. Yes, more people today are trying gardening than ever before, but many new gardeners never saw their parents or even grandparents garden. The whole thing is totally new to them. How are they supposed to guess that a zone 5 label means a plant is hardy in zone 5… unless it’s a bush rose? Even if you told them, it seems so ridiculous they probably wouldn’t believe you.


Bush rose killed by the cold.

How many gardeners in colder climates lose their not-really-zone-5 bush roses each winter? I’ll bet that at least half are toast by spring. It’s unfair to expect beginning gardeners to know that, when it comes to bush roses and only bush roses, zone 5 really means zone 8. Yet if they have a bad experience gardening, they may gave up a hobby that should be fascinating, healthy and fun.  And that’s unfortunate for the gardening world… and the nursery with the lying label loses a client.

Truth in Advertising

Ideally, the hardiness zone given for any plant ought to be its real one. Of course, I fully understand the dilemma of a nursery owner: if he gives “zone 8” as the hardiness zone for a hybrid tea rose, he’ll scare away any gardeners from zone 7 down. I therefore suggest the following compromise. Why not label the plant as “zone 5 with winter protection”? That would make things much clearer. Even a beginner gardener would certainly understand he or she needs to do something to protect the plant from the cold and would, with luck, get information on how to do it from the garden center selling the plant.

Shrub Rose Labels Tell the Truth


Hardy shrub rose ‘Winnipeg Parks’, zone 2.

Oddly, the same nurseries that lie about the hardiness of bush roses tell the truth about shrub roses! These roses are bigger, fuller plants and most are naturally more cold resistant (hardy) than the bush rose trio: hybrid teas, grandifloras and floribundas. Nurseries proudly list their true hardiness zone on the label: 2, 3, 4 or 5, depending on the cultivar. No winter protection is needed for these hardy roses as long as you plant them in their proper zone, or a warmer one. Thus, a shrub rose labelled “zone 2” can be grown in zone 2, but also in zones 3, 4, 5, 6, 7, 8 and 9 (most roses have a hard time with tropical climates: zones 10 and above). And a shrub rose bearing a “zone 5” label will grow, without protection, in zones 5, 6, 7, 8 and 9.

Make Life Easier

Larry paresseux 1 mg copyAs a laidback gardener, I strongly encourage northern gardeners at least to prefer hardy shrub roses to frost susceptible hybrid teas, grandifloras, and floribundas. After all, one of the  basic principles of laidback gardening is to stick to plants adapted to your climate. Not needing to protect a plant for the winter means less work not only in the autumn, when you cover or bury the plant, but also in spring when you remove the protection. So go with shrub roses: they’re much easier to grow!