Time to show extra love to your houseplants

Winter is a great time to show a little extra love to your houseplants, which brighten any dreary days.

I’d suggest fertilizing houseplants as they begin new growth. Try low dosages of organic fertilizers or a very dilute, balanced granular fertilizer, rather than stronger formulas, at this time of year. Increase fertility levels in a couple of months. If you notice white salt markings on terra cotta pots, this indicates the overuse of fertilizer or improper watering. You might want to flush out the soil of over-fertilized plants with plain water, as the buildup of salts from fertilizer can damage the plants.

Fall raspberries? Prune to the ground

It's never too early to start thinking about your raspberry plants. Raspberries can grow into a tangled mess and produce poorly, if not pruned properly. Prune fall-fruiting raspberries (fruit between August and October) back to the ground now to produce one crop of fruit. Most autumn-fruiting varieties are primocanes that produce fruit in their first year of growth. Cut the old canes as close to the ground as possible so that buds will break from below the surface of the soil. New canes will grow and set fruit later in the year. If the canes are not cut low enough, fruiting laterals may form on any remaining cane portion. These fruiting laterals will not be as healthy. Summer fruiting varieties are usually floricanes, which fruit in the second year of growth and require different pruning techniques.

Keep watering evergreens

Do you have a holiday evergreen in a pot? Be sure to keep watering any evergreens that are planted in containers outside when temperatures are warm, and conditions are dry. Evergreens continue to lose water through their leaves during winter and can be affected more quickly as temperatures begin to warm up.

Leave mulch in place

With all the recent warm weather, it’s best to leave mulch and leaves on beds to help protect plants since more normal late-winter cold weather will likely return; last year, for instance, there was a spell of severe cold in the middle of March. The warm days make it tempting to start cleaning up beds. It’s fine to cut back perennials if you want to get a jump on spring cleanup. Avoid working in beds with wet soil. I leave fall leaves on my garden beds to serve as a natural mulch, which decomposes over time and improves the soil.

Bring spring indoors

Ready for spring? While pruning, consider bringing spring indoors by forcing spring flowering tree and shrub branches. Good choices for forcing now include serviceberry (Amelanchier), magnolia (Magnolia), flowering quince (Chaenomeles), forsythia (Forsythia), crab apple or apple (Malus), flowering cherry (Prunus), and redbud (Cercis).

• Tim Johnson is director of horticulture at Chicago Botanic Garden, chicagobotanic.org.