The Garden in January
I tried to
push a metal plant label back into the ground yesterday and it wouldn't go even
an inch into the ground. Despite the cold, a walk through your garden in this
weather is worthwhile, simply to see first hand how your plants are responding
to the low temperatures. Plants that we've grown accustomed to seeing in an
evergreen or semi-evergreen state have gone completely dormant. One plant, the
beautiful Euphorbia x martini 'Waleuprhud', has been evergreen in my garden for
4 years and is at its most gorgeous through the winter months. Now the leaves
are dessicated and the whole plant has flopped to the ground. Fortunately this plant is hardy to zone 6, so
I'll cut it back when the weather warms to above freezing. I'll cover it with a
light layer of dry leaves, and wait for it to rebound in the spring. A hardiness zone
refers to the average annual minimum temperature that a plant can withstand.
Each zone gives a range of 10 degrees. Plants in zone 6 can survive zero to
minus ten. Plants in zone 7 can survive ten to zero degrees. Hardiness zones are also divided into
"a" and "b" categories which narrows the window further. Zone
7a plants are hardy from five to zero degrees. Zone 7b plants are hardy from 10
to five degrees. One of the most interesting discussions of hardiness zones
I've found is available in the back of the Plant Delights Nursery catalog
(www.plantdelights.com). It notes that in areas with lots of snow cover, plants
can withstand colder temperatures due the insulating effect of the snow. It
also points out that cold temperatures for one night are not the same as cold
temperatures that last for weeks. A plant's cells may be damaged only slightly
by one night of deep cold and begin to heal as the temperature warms up,
whereas cell damage may become permanent if the cold temperatures stick around
for several days. To further complicate matters, the time of year can affect a
plants response to cold temperatures. If a cold snap hits one night in early
fall while the weather is still fairly warm, plants may die from temperatures
they normally would withstand because they are not yet acclimated to the cold
weather.
The heavy
snow from the Christmas storm broke many plants and bent others over. Some
plants can recovers from bending better than others. I have seen 20' tall Hollies stand up again after being bent with
the tops touching the ground. It took several weeks for the plants to move back
to upright. At this time of year, prune only the minimum necessary on damaged plants.
Removed jagged or ripped branches and where possible, prune back to the main
trunk just outside the collar to improve healing. If you have a tree that has
lost its main leader, do a little research before grabbing the chain saw. It
may be able to produce a new leader. A light layer of leaves over perennials
adds protection for plants that might have been planted late last fall.
Otherwise, perennials and grasses will fend for themselves until spring.
Now for
some good winter news. This is a good time of year to look at buds on trees.
Buds are one of the best methods of identifying trees, and observing them
closely in their winter state reveals much about how the trees grow, how the
leaves form, and where the flowers are produced. Many trees have exquisite
buds. Check out the buds of the American Beech tree – long, shiny copper
colored, or the buds of the deciduous Magnolias covered with silky grey fuzz. Getting
out to look at buds is a good way to knock back the cabin fever and more fun than salting the walks, or hauling
brush. Spring begins in February, so next month's news will include a list of
plants in full bloom and where to go see them. Meanwhile, stay warm!
~Amy Fahmy
