Thursday, December 8, 2011

Winter Plant Care - Prepare for the Cold

Cold, Wind, Snow....Winter's Harsh Realities

Very cold, sub-freezing temperatures are forecast  for my Zone 6 garden in southwest Ohio.  I'm inclined to wrap up on the couch with a quilt and a plate of munchies nearby.  As my poor, darling plants are out there facing the elements, I know I need to take some steps to protect some of the more delicate ones from the winter cold.

Mulching is probably the easiest method to insulate roses.  I pile the chopped leaves up around the canes to 15" - 18".  The root and stem joint, or bud union, should be covered.  Certainly the canes may have winter die-back, but they can be pruned in the early spring.  Hybrid Teas are probably the most tender of the roses; shrub roses tend to be more hardy. 

These two pictures show different types of winter damage - the evergreen in the container got its roots too cold.  The pathway on the left shows winter damage of wind burn and salt damage.

Plants in containers are very susceptible to drying out and frozen roots.  Watering during the winter should be continued. Water acts as an insulator in the soil.  Frozen water is 32 degrees F.  Dry soil with open air pockets can allow the air spaces to match the sub-zero wind chills of the outside temperatures. 

I generally do not burlap my containers.  I have said before, I'm a lazy gardener, so I tend to take a less time consuming approach.  I gather my containers - some need the aid of a 2-wheel dolly - and I group them up near the west side of the house. I mound leaves around the pots to protect the roots from being exposed to cold winds.  Some would tell you to use the north side walls, out of the sun, but I haven't had any losses (yet).  The overhang is 3' wide, so again, watering manually is needed. 
A garden club friend, Marian, has 20-30 bonsai plants in some pretty, yet shallow containers.  Most are trees and evergreens that typically go dormant.  She has a trench near the house foundation in which she buries her pots. 
The bubble wrap can be purchased to wrap containers and add another layer of insulation. 

This simple burlap wind screen can protect your plants during winter from windburn, salt damage, and sun scald. 

Sun, wind, and cold affect broadleaf evergreens like rhododendron, azaleas, and holly.  Moisture can be reduced in the leaves during the winter.  Frozen ground reduces the uptake of water through the roots.  Screening these evergreens with burlap can help reduce wind damage, and offer shade from winter sun. 

Anti dessicants like Wilt Pruf offer a film on the leaves to reduce moisture loss to our winter evergreens.       ( Spray on your Christmas tree too, to have the holiday decorations a little longer.) Two products are Wilt Pruf or Wilt Stop.  Both can be found at the Amazon Store, garden centers, or hardware store.

Mulch gardens only after the ground is frozen.  Mulching too early may cause the ground to not freeze and plants will not go completely dormant.  Consequently, this semi-dormant condition, call deacclimation, can allow roots to be damaged by the cold even if this plant is labeled hardy to your zone.

Mulching at the right time can keep plants from 'heaving' (plant rises out of ground exposing more shallow roots). My heuchera - coral bells - are known for this.

Tying these arborvitae can protect the splitting of leader trunks - a common result of heavy snow.

Deciduous tree trunks are also susceptible to sun scald.

Thin barked trees like maples, young crab apples, or flowering fruit trees, and newly planted young trees may need additional protection.

In very cold weather the tree trunk can severely crack. The lack of water uptake is one reason. The sun itself, can allow the south facing trunk to be 60 degree while the back side, can be 32 degrees. This cracking can open your tree to insects and diseases.

Trunk wraps are also beneficial for protecting bark damage from animals.  Rabbits, voles, and deer can get hungry, and our plants are fair game! 

Voles, a small field mouse-like critter that loves to eat roots.  I've had hostas come up (not) missing in spring thanks to the friendly neighborhood vole.  Surface trails in the grass or snow give us a clue to the culprit.

Mulch and debris make a good cover for voles.  Clean areas around plants can minimize vole activity.  A 1/4" screen opening, extending 3-4 " below the surface around a susceptible bed can also lessen vole damage.  

Rabbits will  strip bark from trees and shrubs.

Barriers and repellants are useful deterrants. A 1 inch wire mesh around plants, at least 15" to 18" will work well.

Deer barriers need to be built around the tree so that the deer cannot reach into it to eat. Spray deer repellents like Liquid Fence work IF you are determined - respray after a rain. This urine based solution will wash away.

I know winter seems like a long cold season, but winter plant care will ensure spring will be its own reward.

What steps do you take to give plants winter protection?

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