How soon in the spring can I start cleaning up the perennial bed? It seems that many plants are coming up, but quite a few look like they have not survived the winter.
First, let’s discuss those “dead” plants. There are some perennials that are very slow to wake up in the spring. Common ones include some varieties of Hydrangea, butterfly bush, Baptisia (false indigo), many ornamental grasses and Russian sage (Perovskia). The sage is particularly frustrating because the stems from last season do indeed look dead. New growth arises from the bottom 6 to 10 inches of the plant so do wait for new growth before pruning or writing it off. Some annuals freely self-sow later in the spring, when frost should not be an issue. If you clean up your flower bed too early, you may miss these volunteer seedlings. Particularly late to germinate are Verbena bonariensis and Cleome. Because of these late bloomers, it’s always a good idea to have durable plant labels in the garden.
As far as when to clean up, as long as the soil is not too wet, feel free to dig out those pesky weeds that always seem to spread rapidly at the first sign of good weather. Dig carefully so as to not disturb any perennials in the area. Watch for plant crowns that have heaved up over the winter and gently push them back into the soil.
When should I prune?
I receive many queries as to when to prune various plants in the garden. As a general rule, if the plant blooms in the spring, you want to wait until after it flowers before pruning it back. Examples of this include lilacs and forsythia. Otherwise, you can usually prune after the plant flowers in the summer. Hydrangeas have so many varieties that there are special rules: https://tinyurl.com/y2m5n9g4.
As for fruit trees, get them pruned before the sap starts to run. Raspberries and other cane fruits can be pruned both in the fall and in early spring to eliminate crowding, dead and damaged canes. Grape vines can also be pruned in early spring but they seem to thrive no matter when they are cut back.
My evergreens seem to have survived this harsh winter but some of them are brown all over on one side. What is this? Will the plant recover?
This sounds like winter burn. Caused by harsh winter temperatures and drying winds, sometimes the plants are so affected that they can’t survive. But most of the time, the plants will continue to live but the brown tissue cannot be saved. Prune out dead, brown, damaged or dying tissue in mid-spring after new foliage is produced.
This site offers a detailed account of the causes and cures of winter burn as well as what to do with these damaged plants: https://hort.extension.wisc.edu/articles/winter-burn.
How can I tell what is wrong with my garden plants when they are having problems? Is there a diagnostic clinic online so I don’t have to take plant tissue to a distant laboratory?
My favorite site for checking plant diseases is http://vegetablemdonline.ppath.cornell.edu. You can search by the individual plant or by browsing the extensive photograph displays.
Since garden damage can also be caused by insects, it’s important to recognize both harmful and beneficial pests as well. These two sites should help: https://tinyurl.com/y2dskypo and https://tinyurl.com/yxp2x3b8.
Some garden problems are caused by nutrient deficiencies in the soil. Although I have yet to find a thorough pictorial guide to nutrient deficiencies in the garden (I’ll keep looking), this site may offer some help: https://growabundant.com/nutrient-deficiencies.
Beverly Carney can be reached at email@example.com.