Early Fall!
Repot that African violet when it sticks its neck
out
Dear Janet,
I have no problem growing large (10-inch diameter) African
violets. My problem is the dropping of bottom leaves after the
plant is about 3-4 years old. The leaves still look very healthy
but the stems get soft. I've lost so many leaves, the crown is
long, bare and hangs to one side.
H.,
Dear H.,
I'll let The Royal Horticultural Society Dictionary of Gardening
(Stockton Press, NY) answer for me:
"As a plant matures a 'neck' develops when spent leaves are
removed from the main stem. Repot... by cutting away the bottom
third to a half of the rootball thus lowering the plant into the
fresh potting medium for new roots to grow from the main stem."
"When the neck is too long for this treatment cut through the
main stem an inch below the leaves, trim the stem below the leaves
into a cone shape and pot into a small pot with the leafstalks just
clear of the potting medium. Place the pot in... bright indirect
light at... high humidity such as in a covered... propagator."
Now, for that other question -- "Why?" (Thanks to R.A. for
reminding that there are always people out there who will also add
"why?" after asking "how?")
The neck develops because this plant from tropical Tanzania in
Africa evolved in an environment where soil is always building up
with rotting plant debris. The continually growing, dense rosette
must lose bottom leaves as they become too shaded by new growth to
be productive. As the plant drops leaves it also rises, keeping
itself above all the leaf litter that accumulates on a rain forest
floor by means of its elongating stem. As each point on the stem
that once grew a leaf is enveloped in cool, moist organic matter,
the point is stimulated to resume growth. Roots form there.
To grow these plants in pots, we simulate the condition they
have evolved to need -- increasing soil level -- by repotting,
deeper.
Coral bells (Heuchera species) and some other woodland
natives that we grow in gardens follow this growth pattern, too. If
we grow them in a place where the soil level has to stay the same
year after year, we give them the same treatment, digging them up
to replant them deeper every few years.
Dear Janet,
Is it okay to use a kill-all product to edge a flower bed?
J.,
Dear J.,
It's acceptable but I don't recommend it. It doesn't meet
my standard for a flower bed because it can't make a neat straight
edge like a cut. Also, weeds on that edge are highly visible as
they yellow and die. That's not what I want to see on the front
edge of my flower beds.
Herbicide as edging is hard to control. The herbicide can drift
or splash onto desirable plants, which tend to die more readily
than the weeds. Most people don't even know any weed killer has
drifted until they see the dead flowers. Yet this tactic is widely
employed in places where labor is in short supply, such as at
arboretums. So if you're careful and will accept some collateral
damage, it can work.
Your term "kill-all" concerns me. I hope you aren't thinking
about using one of those products that kills anything that tries to
grow in a spot and is effective for a whole season with one
application. For edging, use a product such as Round-up (active
ingredient glyphosate), which kills what is growing there now but
doesn't affect what sprouts there later. Round-up is absorbed
through foliage, not through the root.
Season-long killers poison the soil itself. Those like Triox
Total Vegetation Killer (active ingredient Prometon) move from soil
into the root and have long lasting and often unexpectedly wide
impact. For instance, if there are trees whose roots occupy the
same space where you poured something root-absorbed and
long-lasting , then that tree is likely to lose some branch tips or
limbs, or die. Ditto for shrubs with roots in the area.
Always read the label on a pesticide before applying it. Be sure
any herbicide you intend to use for edging says an area may be
replanted immediately after application. Heed warnings! The label
on Triox explains that it shouldn't be used over the root systems
of desirable trees and shrubs.
How to know what other plants have roots in the area? Look up.
If you are anywhere near the outer ends of the branches, then you
are standing on that tree's or shrub's roots.
Short report
Still okay to seed a lawn.
M.J. needs to reshape a lawn to add to the edges and
wonders if it's too late to do this by seed.
Although we're past prime lawn-seeding time, seed you spread now
will probably still germinate and take root. Remember to give it a
sprinkler assist on any hot, dry days.
Green thumbs up
to mowing the leaves as they fall and letting them stay on the
lawn. This replenishes the soil, returning to the earth nutrients
used in making those leaves. You'll rake less and the grass will
benefit.
Green thumbs down
to dousing houseplants with pesticides unless there is a visible
need. As you bring them in from outdoors they are the healthiest
they ever are! Just rinse the foliage and wipe down the pot.
Originally published 10/4/03