The Cupertino Courier

Gardening

Winter frost that'll be forgotten left things looking pretty rotten

By Tony Tomeo

Now that the weather is getting rainier and warmer, the damage from earlier frosts is looking downright rotten. Withered brown foliage is now turning blotchy black with mold. Damaged succulents that have turned a sickly gray and gone limp are now melting into slimy mush. When the weather is pleasant between rain, it is tempting to go out and clean up the garden.

Fortunately, it is probably late enough to do just that without making the problem worse. The only reason for leaving the unsightly damage so long was to protect the damaged plants from additional damage. Because frost or a "hard freeze" is unlikely this late and after the rainy season has started, this protection is no longer necessary.

Withered, damaged foliage that was left to insulate viable stems and buds below is now only shading new growth and causing it to etiolate (stretch toward sunlight). Damaged stems can actually interfere with structural development (branching). Removal of the debris will promote healthier growth on more substantial stems, and can improve development of structural integrity among trees and large shrubbery.

Premature pruning to remove damaged foliage and stems could have stimulated early emergence of new foliage, which would have been even more sensitive to frost than the foliage that was damaged earlier. However, foliage that develops now should be safe. Pruning will help the affected plants to concentrate their resources into vigorous new growth instead of trying to restore damaged parts.

Now that new growth is beginning to appear below damaged growth, it is easier to see how far back the damage extends. Damaged plant parts can be pruned back at least to where new buds are visible. Plants such as princess flower (Tibouchina urvilleana) and bougainvillea can be pruned back even farther to larger and healthier shoots that are below the highest (farthest from the roots) viable buds. Some of the highest buds that are barely viable now will probably succumb to damage later and be overtaken by lower shoots anyway.

The remains of large jade plants and similar succulents that were frozen can likewise be scooped up and removed, leaving only roots and any undamaged trunks and stems. I prefer to wait for them to dry a bit so that they are not quite so heavy or messy. Unfortunately, rain will keep them mucky and unsightly for a long time. It is, therefore, probably better to remove this material before it attracts flies and damages the ground cover or lawn that it is lying on. On the compost pile, it should be spread out to weather and deteriorate instead of putrefying.

The best way to avoid frost damage in the future is to avoid planting plants that are sensitive to frost. This, of course, is too limiting for many of us who enjoy gardening with plants that are less than ideal for the local climate. If sensitive plants must be used, they should be located where they will be less susceptible to frost, such as under eaves or dense, evergreen shade trees. Eaves of older uninsulated homes are safest because warmth lost from within is found again outside.

Flower of the Week:
Lily-of-the-Valley

Grown for its colorful new foliage as much as its delicate pendulous floral trusses, lily-of-the-valley shrub, Pieris japonica, is attractive all year. Short tassels of greenish white, pink or ruddy brown flower buds develop in autumn and stay through early winter. These buds bloom into tiny, waxy white flowers by the middle of winter to spring. Some types have pale or rosy pink flowers. As flowers fade, bright pink, red or bronzy new foliage emerges. By the middle of summer, the remarkably glossy foliage has mellowed to dark green. Foliage of "Variegata" and a few other variegated cultivars has silvery white margins. The most popular lily-of-the-valley shrubs are generally less than 6 feet tall and wide. Some are only about half as large. A few get to 9 feet. Like related rhododendron and azalea, lily-of-the-valley shrub prefers an eastern exposure, where it gets plenty of sunlight in the morning but is shaded during summer afternoon heat. Selective pruning instead of shearing will preserve the naturally limber and irregular branch structure.

Listen to Tony Tomeo's 'New Image Garden Report' Friday mornings at 8:10 a.m. on KSCO-1080 AM (or online at www.ksco.com). He can be reached at www.ttomeo@newimagelandscape.com or 408.358.2574.