Perennial Frequently Asked Questions

Perennials: Frequently Asked Questions

Perennials

When should clematis be cut back, if at all?

Twice-blooming clematis, those cultivars that flower in the spring or summer and then again in the fall, need only a light shaping or pinching off of the tips. The idea is to stimulate growth from the top. Clematis that bloom in spring only can be cut back after they flower to preserve the shape and prevent the vines from becoming overgrown and tangled. Summer or fall blooming clematis can be trained with a spring pruning (or early fall in mild climates). Cut these vines way back to 6" or 1' above the ground when young, to 2' or less as they mature.

How should I prepare my soil for spring planting?

If you live in an area where the ground freezes, wait to work the soil until a fistful crumbles rather than stays stuck in a tight ball. When the soil becomes workable, rototill or dig in organic amendments such as shredded leaves, compost, manure or peat moss. If you're gardening in poor, compacted soil, sow a quick cover crop of nitrogen-rich clover, annual rye or buckwheat in early spring. These "green manures" fix nitrogen in the soil and loosen it up with their vigorous roots. Turn cover crops over into the soil before they bloom and go to seed. If your soil drains poorly, consider building raised beds. This is the best strategy for growing trees and shrubs, including roses, in a heavy clay soil.

How should I prune flowering shrubs?

The general rule of thumb is to prune shrubs that bloom on new wood — such as hybrid tea roses and butterfly bushes — in late winter or early spring while they are still dormant. Cut back shrubs that flower on old wood - including lilacs, hydrangeas and forsythia - after they flower.

What can I plant for winter color in my yard?

Many shrubs and trees, even those that are leafless in the winter, offer pleasing and colorful seasonal effects. Established climbing hydrangeas, birch trees, various kinds of maples and Contorta trees all have graceful silhouettes or colorful bark that stand out against the winter skyline. Ornamental grasses, including Maiden Grass ‘Gracillimus’, stay attractive throughout the winter. For early-flowering color, look to hardy perennials such as Christmas Rose Hellebore and Lenten Rose Hellebore. The bright red new foliage of shrubby Pieris ‘Variegata’ also perks up the late winter landscape.

Amaryllis

How do I store my amaryllis bulb when the plant goes dormant?

All amaryllis and other bulbs need a rest period in order to bounce back with another show of foliage and flowers. When the leaves of your amaryllis begin to yellow and wither, stop watering. The bulb can be stored either while still in pots or removed, cleaned of excess soil and placed in a paper bag filled with dry peat moss. Store amaryllis bulbs in a cool, dark place for at least three months. When the bulb begins to sprout at the top, replant it in fresh soil, water and bring it into a cool, sunny room to restart the growth cycle.

Bonsai

How often should a bonsai be watered indoors during the winter?

Water bonsai plants frequently. In their shallow pots, with limited root space, they can easily dry out. As soon as the soil surface begins to dry, place the pot in a baking pan filled with about an inch of water. Leave the pot standing in the water until the soil surface becomes moistened. In between waterings, mist the bonsai’s leaves with water from a spray bottle.

Orchid

Why won't my phalaenopsis orchid rebloom?

When orchids refuse to flower, they usually aren’t receiving enough light. When your plant is actively growing and developing new leaves, move it to a bright, east-facing window or place it under a grow light during daytime hours. This will help stimulate formation of new bloom spikes. Mix in diluted orchid food when you water to promote healthy leaf and flower bud growth. Phalaenopsis orchids also prefer warm indoor temperatures of 75-80° F during the day and 65-70° F at night. They thrive in high humidity, which you can furnish by placing a saucer of damp pebbles under the pot.