THE POT SPOT

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Rooted for Winter Growth

As winter approaches and the outdoor herb
garden’s seasonal show winds down, many devoted dirt gardeners go
into hibernation, to emerge in the spring eager once again to get
their hands dirty. Winter is an essential period of rest for both
plants and people.

Or not. Some of us don’t want the show to be over, no matter how
bad the weather is. So we turn to pots. Containers are essential
tools not just for the urban apartment-dweller growing parsley and
basil on a kitchen windowsill, but for herb gardeners of any
stripe, especially at this time of seasonal change.

A container herb garden is more than just a way to bring a piece
of the outdoor perennial garden inside; it also can be insurance.
Our most treasured plants — those that were given to us or have a
special memory attached, unusual cultivars that are difficult to
find or expensive to purchase, ones that are barely hardy enough
for the climate, slow-growing plants we’ve had for a long time —
will outlive the winter if we grow a piece of them in a container
on a sunny porch or windowsill, or under lights in the basement or
spare room.

The easiest way to do this is to root cuttings of the plants in
question. Do it right now, while the plants still are growing
vigorously and before they’ve been hit by the first frost. Once a
plant’s growth slows in response to shorter days and cooler
temperatures, stem cuttings will root less readily — sometimes not
at all — so don’t delay.

Unlike seed propagation, a stem cutting guarantees that the
offspring will be exactly like the parent plant. This is a
necessity with cultivars that offer a particular fragrance or color
variation but don’t breed true from seeds.

BE SELECTIVE

Few people have enough adequately lit space indoors to winter
over every plant they have outside during summer. And some plants
just aren’t worth the effort, even if you do have the space. So
when you take your cuttings, discriminate.

Skip the annuals and short-lived tender perennials such as dill,
cilantro, summer savory, marjoram and basil, as by now those plants
are nearing the end of their life cycle and won’t make it through
the winter anyway. They are easy to grow from seed if you do want
them in the wintertime.

If the aim of your indoor winter garden is primarily culinary
herbs for mealtimes, don’t bother rooting herbs that hold onto
their flavor well when dried, such as thyme, oregano and sage. Many
herbs lose much of their flavor on drying, or the flavor changes
considerably, but these three are usable right from the pantry.
They’re also tough plants in the garden and will survive almost any
weather, so there’s no cause for worry when transferring them
indoors.

Choose only healthy plants and pass over any that look stressed
or show any sign of pests or disease. Life indoors is hard enough
without starting off disadvantaged.

ROOT THOSE CUTTINGS

You can always just cut a few inches off the tip of a stem,
stick in a glass of water on the windowsill, and in a couple of
weeks you’ll have roots. Maybe. That’s how we did it as kids, and
for easily propagated herbs such as mints, this technique still
works just fine. Here’s another way to root a stem cutting.

First, have your small pots clean and rooting medium ready,
whether you buy a bag of porous potting mix for seedlings or mix
your own formula from peat moss, perlite, vermiculite, compost and
other ingredients. Moisten the potting mix well, and fill the pots
about three-quarters full of moist potting mix. Using a pencil or a
chopstick, poke a hole in the center of the mix for the stem.

Using a clean, sterilized knife or pruning shears, cut off the
top 3 to 5 inches of a non-flowering stem, making the cut at an
angle to expose as much of the inner stem to the potting mix as
possible. Strip off all the lower leaves to prevent their rotting
in contact with wet potting mix and to encourage root development.
If the leaves are large, clip back about half of the largest ones,
thus reducing the surface area from which moisture is lost to the
air.

Dip the cut end in rooting hormone, a powder available at garden
centers that encourages speedier rooting, particularly in
woody-stemmed plants. Take care with the rooting hormone, as it can
irritate the skin, and don’t inhale the powder. Coat the cut end
lightly, knocking off the excess.

Immediately stick the stem into the hole not quite to the bottom
of the small pot. Firm up the potting mix around the stem to ensure
good contact between stem and potting mix, adding more as you need
it to fill the pot to within an inch or so of the top.

Keep the potting mix and the air surrounding the stem uniformly
moist, either by misting it several times a day or by placing a
kind of plastic tent over it (a plastic freezer zip-bag positioned
loosely over the pot will do the trick) to hold moisture in.

Now wait and see if it works. Whether it takes a week or a
month, you’ll know you succeeded when you see new growth at the
tip, which means roots are forming below.

POT SPOTLIGHT

Need a suggestion for an herb to root from a stem cutting? How
about pineapple sage (Salvia elegans)? It’s a good candidate
because it’s a tender perennial and won’t survive the winter in
many climates, and it roots readily. And while it becomes a huge
plant outdoors in the right setting, its size is more manageable
when contained in a pot. Its lovely light green leaves, brilliant
red flowers and delicious pineapple scent chase away the winter
blues.

Kathleen Halloran, former editor of The Herb Companion, is a
freelance writer and editor now living in Las Vegas, where she
grows herbs in containers.