MORE HOW-TO's on
overwintering other tender perennials -
The degree of difficulty in overwintering and growing Canna,
Gladiola, Caladium, purple Oxalis, tuberous Begonia, Dahlia,
Geranium, or Amaryllis again for a new season is different for
each, but some are very easy. Just a cool dark corner in
the basement is all many need as long as you condition them
correctly in autumn.
All perennials have
a dormant period - hardy perennials and
tender perennials alike. The only
difference is that tender perennials
need their roots to be rescued before
our winter freezes their roots. As
long as you leave them out in the garden
long enough in the fall for them to feel
some of their natural dormancy triggers
such as lessening daylight hours and
changing temperatures, and finally a
light frost, it can be as simple as
digging them out of the ground and
putting them somewhere where they won't
The mistake many
gardeners make is digging up tender
perennials before the plants have a
chance to experience all the necessary
dormancy triggers. The plants then
continue to try to grow since they
didnít receive all the dormancy triggers
and basically, just plain don't know
that the season is over! They'll
die over winter in their attempt to grow
without sunlight or moisture.
Most of the above mentioned savable plants
are bulbs, tubers or rhizomes making them
very simple to overwinter. Others are
fibrous rooted plants adapted to a hot dry
climate, like Geranium (Pelargonium), where
dormancy is triggered by the dry season.
Fibrous rooted plants are best stored with
some soil protecting their finer roots, but
kept almost bone dry and therefore dormant.
Hereís the rules of thumb.
AFTER they have been through a
that browned and wilted leaves, late October
usually, dig tubers (e.g. Dahlia,
Colocasia), bulbs (e.g. Calla, Amaryllis),
corms (e.g. Oxalis, Gladiola) or rhizomes
(e.g. Canna, Ginger,), out of the ground.
Cut the stems down to approx. 3".
Remove any large clumps of dirt and put the
bare roots in
a dry, breezy, shady place for about a
week - indoors if there's any chance
temperatures will go below zero. All
surfaces must be well dried, including the
cut stem end. Mold and fungus is the main
enemy in dormant storage and itís best to
err on the too-dry side than the
not-dry-enough side. Think potato. Think
of what happens to a potato thatís stored
with even just a bit of moisture on the
surface Ė mold and rot. Youíre aiming
at a completely dry exterior and a moist
fleshy interior Ė just like a potato.
Once all surfaces are dry, pop them into a
cardboard box, paper bag, or wrap in
newspaper. No plastic! They need to breathe
to allow for that little bit of air on the
surfaces to keep them dry. Whatever
you store them in, they shouldn't touch each
other. I wrap each loosely in
newspaper and store the wrapped packages in
a large pot without a cover on it. The
newspaper keeps any light out and keeps a
bit of air flowing. Put the box or pot in a
cool dark spot where the temperature NEVER
goes below freezing.
Thatís it! you basically can forget
about them until itís time to stir them out
of dormancy in late winter by
gradually reintroducing them to
sunlight and water.
In March/April, depending on the speed of
growth of the particular plant, pot them up
in some clean fresh potting soil and water
lightly. A warm spot will speed things
along. Once new growth appears, start
watering with fertilizer mixed at 1/2
strength, and get them into as much sunlight
as possible until all risk of frost has
passed when they can go into their permanent
outdoor spot. Exactly when to bring them
out of storage depends on whether you have a
very sunny window or not, and the particular
plant's speed of growth. If you donít
have such a place, itís better to leave them
until late April or so that they can go
straight outdoors when spring brings warm
A few extra tips Ė
fat fleshy stemmed plants like Canna or
Colocasia, cut them to within 2-3" of the
root and dry them upside down to make sure
all moisture drains out of the fat stem of
leaves at the base.
tubers and rhizomes whole - leave dividing
into smaller individual sections for spring
when thereís far less danger of the exposed
cut surfaces developing mold. When
dividing make sure each piece has an ďeyeĒ
or growth point.
- Dahlia tubers have their new growth bud at
the point where the old stem meets root.
With a sharp knife, be sure to get a piece
of the old stem still attached to the tuber.
A fat fleshy tuber without that little top
bud will give you nothing.
Conversely, just a tiny little tuber with an
undamaged growth bud will give you a lovely
- Geraniums should be cut right back to just
a few main stems when brought out of
Have fun and try Overwintering other tender
perennials - there's certainly nothing to