Saving cannas, begonias and other tender plants
Please tell me how to keep my cannas over winter. Last
year I dug them up after the first frost even though the leaves had
not turned brown. I then knocked the dirt off each; some I split
into more plants and let them sit in the garage until early
December. I then put peat moss in boxes, laid the plants on top and
covered them with peat, newspapers and burlap.
This spring when they were uncovered, all were soft and
mushy. Someone said they should have been thoroughly dried and
placed in the basement in a cool dark spot, not an unheated garage.
- M.A. -
There are at least three options for saving cannas:
Canna as houseplant
One, grow them as houseplants. Pot them up and bring them in. Do
not pot them in garden soil, which often leads to root rot. Use
soilless potting mix, which provides far better drainage in a pot
than even the best garden soil.
Bare root storage
Two, cut the tops back whenever you like. Dig out the root mass
and let it dry stem-side down in an airy, frost-free place, until
most of the soil will fall away. Wrap the unbroken root mass in
newspaper and put it in a paper bag in a dark, 50- to 55 degree
place with 50 per cent humidity.
Alternatives to newspaper wrapping are to bury the roots in a
box of sand or barely moistened peat.
The idea is to keep roots cool and dark so they don't start
growing again, padded against bruises and nicks that could open the
flesh to fungus infection, and moist enough that they don't dry and
die. Old-time, dirt floor, unheated Michigan basements or "root
cellars" are ideal for storing roots. Modern basements are usually
too dry and warm, so the keeper has to check stored roots now and
then to add a few drops of water or remove sprouted and rotten
Root cellar or root pit
Option three was once standard procedure on some farms to save
root crops like potatoes or carrots for winter consumption. Dig a
pit three to four feet deep, so that its bottom is below the frost
line. Put your roots into the hole, then backfill it with loose,
dry leaves or straw, mounding it a couple of feet high. Then cover
all of that with a tarp, a board or soil and let Nature care for
If rodent damage is likely, line the hole with hardware cloth or
a metal garbage can. Put in straw, the roots, then more straw or
leaves. When you fill the can or reach the top of the hardware
cloth, put the lid on the can or bend the sides of the hardware
Your cannas rotted for two reasons. They went into storage
injured. Every cut is an injury, a place where rot can begin during
storage. Cut up roots only as you replant in spring. Also, the
roots were not sufficiently insulated. Keep them in a root cellar,
Michigan basement or storage pit.
When should I dig up my caladium and begonia roots and
how do I store them for next season?
Dig them any time now. Use option one or two from the preceding
Don't use option three, as a storage pit may become too cold for
caladium and begonia. Several years ago volunteers stored some of
our tender roots this way. In spring, the cannas and dahlias looked
as they had when we first buried them but the more tender caladiums
and tuberous begonias had rotted.
Recent explosion of mealybug and indoor plant problems
Turn on some grow lights! Many people have complained about how
gray it's been this fall, but few have thought how that might be
affecting the plants that subsist on window light. Less light means
less energy and less energy means the plant can't fend off or hold
down populations of its parasites.
You can wash pests off, pluck them off or kill them with an
insecticide but they'll be back in force if you don't find a way to
give that plant more light.
Bearded iris, forsythia, azalea or lilac blooming in
It's not unusual. Plants that bloom very early in spring often
have internal timers that tell them when to bloom, mechanisms
triggered when a period of cold is followed by a warm-up. Such a
species may require 500 hours of below-40 temperatures to "think"
it has been through winter, then will bloom at the next respectable
warm spell. Later blooming species may need 1,000 hours of cold or
that plus additional environmental cues before they flower.
Given the cold we had this past spring, which chilled plants
after they had bloomed and grown for a time, some plants with
short-winter triggers had nearly met their cold requirement by
Labor Day. A few cool fall nights, then a warm up, and the buds
Don't be alarmed. Such plants rarely "waste" all their flower
buds in fall, and sustain no lasting injury from the precocious
Green thumbs up
to spreading slow release organic lawn
fertilizer now. It goes further than any other fertilization toward
improving a lawn's health.
Green thumbs down
to blowing, shredding, mowing or grinding if
you can rake, quietly. Your ears and your neighbors will thank
Originally published 11/6/04