Cold damage care
Amy Jordan
Thursday, April 12, 2007
Ouch. The recent cold temperatures really hurt the succulent new growth of many of our plants.
As we stare at the droopy mush that is left of our plants, we ask ourselves, “What now?”
That is a good question. And there isn’t a good answer. The best we can do is give it time. The damage will be variable, depending on the type of plant, stage of growth, age of plant, actual temperature it was exposed to, etc. Some flowers or foliage that look badly now, may come out of it. I noticed some tulips that were drooped over this weekend have now begun to raise their heads. That, to me, is a sign of hope.
Most trees, shrubs and perennials will probably bounce back, sending out new foliage within a few weeks. Trees and shrubs have dormant buds that will develop in the absence of those that were killed. Established perennials will probably replace foliage that was lost, but we don’t know what affect the low temperatures had on dormant flower buds. Flower buds that were exposed and are now black or mushy won’t continue to develop. Foliage that is soft and translucent won’t come back, but it doesn’t need to be removed just yet. Also, leave any foliage that still has a green color, even if part of the leaf is bleached out, like what is visible on many of the iris and daylilies. Leave hostas alone for now, especially if they feel firm at the base. Once new growth begins to emerge, clean up foliage that was damaged.
The prognosis for fruits and vegetables isn’t as good. To check the condition of fruit, cut open a bud; if the tissue is black, it was killed, if the tissue is green, it survived. Check vegetable plants for firmness in the stems or roots. If everything is soft, replanting is necessary. Keep in mind that even if the plants survived, they may have been injured enough to significantly reduce productivity and replanting may be the best option.
It is important to reduce any additional stress to the plants, so keep them well watered throughout the season. Avoid heavy applications of fertilizer, which could weaken the root system by encouraging the plant to produce excess foliage. However, a low dose of slow-release or water soluble fertilizer might give plants an extra boost. Wait until you see new growth emerging before applying fertilizer.
Plants that are marginally hardy in this area or ones already under stress may not recover quickly, if at all. Again, wait and see if they will send out new growth. All plants that are not well established, such as ones that were planted last fall, may not have the energy to leaf out again, but give them time.
I haven’t noticed much damage to cool-season turfgrass, even newly planted grass. We may see damage to Bermuda and Zoysia grass when it greens up.
On the bright side, the freeze may have killed young crabgrass plants or silver maple seeds (helicopters). But those darn dandelions still look healthy.
F Amy Jordan is a horticulturist with K-State Research and Extension in Lyon County.