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Get out in the garden: The busy season is underway

Ask the Expert Gardening Boston South Boston
A fallen tree.
A fallen tree. Handout

The busy season begins. Finish garden cleanup. Seed lawns, but don’t fertilize until fall. You can, however, sprinkle bulb fertilizer around emerging bulbs and perennials, though not on top of them. Start cold hardy seeds outdoors and more tropical seeds indoors. Prune and feed roses. Plant cold-hardy plants, but not annuals yet. Move perennials and woody plants that are in the wrong location or require division.

Q. I live in the city and have a tiny garden surrounded by paving stones. I would like to get some dwarf trees or bushes that are . . . able to survive in pots in the yard [which] receives full sun most of the day.

K.M., South Boston

A. It’s easier to grow hardy shrubs than trees in containers. Pieris and boxwood are among the best evergreen shrubs for containers. Gooseberry is one of the easiest fruits for growing in containers. Many kinds of hydrangeas grow well in pots and come in various colors and sizes. Lavender plants and dwarf lilacs have fragrant flowers for both you and the butterflies. I like Bloomerang, a new four-foot lilac that reblooms through August. You can leave all these plants in their pots outside through winter if you move them out of the wind.

Q. Welcome back! We lost a very large pine tree, among others, this winter. We got lucky that it fell the right way. I’m wondering what I can put in to replace it. I wouldn’t want a large tree there again, but maybe smaller trees or bushes. I’m looking to use them as a border, too. These would be planted very close to wetlands and a lot of the time part of the wetlands, with rain. That area doesn’t receive much sun at all.

E.S., Canton

A. This is the best time to plant trees and shrubs. In your photos the site looks like a nice natural area for a native shrub or small tree that tolerates part shade and “wet feet,’’ which is garden talk for sites with occasional flooding or a high water table. Most plants can’t grow there because their roots drown. Small trees that can include downy shadblow (Amelanchier arborea, with white flowers, berries for birds, and good fall foliage) and American holly (Ilex opaca, evergreen with bright red berries). Smaller growing shrubs for “wet feet’’ sites include Arrowwood viburnum (V. dentatum with flowers, berries, fall color), swamp azalea (Rhododendron viscosum, very fragrant), Summersweet (Clethra alnifolia, also fragrant), and chokeberry (aronia). Small evergreens for occasionally damp locations include mountain laurel (kalmia), Leucothoe fontanesiana, and inkberry (Ilex glabra). If you have room, plant a drift of three instead of just one.

If you want something a bit unusual, I recommend trying buttonbush (Cephalanthus occidentalis). This native of Eastern swamps is an easy multi-stemmed shrub reaching about 10 feet. It has a long season of interest with perfectly round one-inch Sputnik-like white flowers in spring that attract hummingbirds and butterflies. The foliage turns burgundy in the fall and provides food for several butterfly caterpillars and, indirectly, young birds. Winter reveals the knobby fruit (beloved by ducks) that gives it its name; it also develops picturesque twisted stems. Buttonbush survives in light shade and, like most shrubs and trees, requires only supplemental watering its first two years or during drought. Wayside Gardens mail-orders a four-foot dwarf variety called Sugar Shack.

EVENTS

Art in Bloom at the Museum of Fine Arts begins with a Friday evening preview, April 27, 5-10 p.m. Boston’s top flower-arranging event combines artistic masterpieces with their floral interpretations through Sunday during museum hours for the cost of regular admission. Visit www.mfa.org/programs for a schedule of both free and ticketed floral programs, including Sunday’s family-friendly entertainment.

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