When to prune salvias this winter?

A field of Mexican sage (Salvia) in full bloom on a summer day. All sage plants benefit from pruning, but timing can vary depending on the variety and climate you live in.

s. I have a lot of plants that will probably need to be pruned again in the winter but I’m not sure how much to prune or when to do it. In addition, it seems to me that they have better protection against frost and freeze if they are not pruned back. Or is this an “old wives’ tale?”

I would appreciate any advice regarding Mexican and other sage, of which I have many, as well as calceolaria and calendrina. I live in the mid-foothills of the San Francisco Peninsula, and most of the plants are on a surface that gets a lot of wind in the winter.

I usually move them closer together in the winter to help protect from the wind. On cold nights I cover them with old sheets, but I wasn’t happy with the results, mildew etc.

Barbara Kaiser, Menlo Park

a. The general rule when it comes to pruning is to prune your hardier plants in early winter and leave the colder plants until early spring. Pruning tends to stimulate new growth, but you can also safely prune dormant plants in the winter.

Each type of plant, of course, has its own pruning schedule, so it’s always best to research the specific plant for tips on timing and how to get it done. Some salvias like to be cut back severely while others only need pruning.

Salvia can be pruned twice a year, once in late fall or early winter and once in early spring. It’s also a good idea to cut off spent flowers and prune the plant after each bloom to prevent it from becoming leggy and woody.

Mexican salvia, also called Mexican sage, can tolerate heavy pruning in late fall or early winter, and some light pruning and cleaning in early spring.

As for Calceolaria (lady’s slipper) and Calendarina (rock purslane), neither plant requires pruning, although you should snip or uproot spent (dead-heading) flowers to encourage new ones.

We are in the coldest days of the year, so it is important to protect your plants, especially those susceptible to frost. Grouping the pots together in a sunny, sheltered area is a good idea, but you can also string old outdoor Christmas lights around them to provide some extra warmth on cold nights.

Using sheets to cover them may seem like a good idea, but sheets can be a problem. Leaves absorb and retain moisture, so they can cause freeze damage if they come into contact with plants. Instead, use a frost cloth or row cover and try to avoid the material coming into contact with the plants.