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Ask the Gardener: Tips for keeping your hanging plants alive

Ask the Expert Gardening
Hanging plants need a weak dose of liquid fertilizer every three weeks.
Hanging plants need a weak dose of liquid fertilizer every three weeks. Taras Garkusha tarasg-photo.com

What to do this week: Buy a rain gauge or check the Globe’s daily weather page. If your garden got less than an inch of rain the previous week, make up the difference. Cut back pest-infested or yellowing foliage on bloomed-out perennials such as columbines, foxgloves, hollyhocks, and day lilies. Most will sprout clean new growth, if not new flowers. Divide and replant crowded bearded iris. Harvest cucumbers before they turn yellow. Harvest only the top 6 inches of broccoli before the buds open, so side branches will continue to produce. Sow seeds of lettuce, cabbage, kale, collards, beans, beets, and other fall crops now.

 

Q. Every year I buy hanging flowers for my balcony. They die in October, and I feel kind of bad. What should I do to keep them alive?

AILEEN BALDELOMARA, West Roxbury

A. Don’t feel bad! Hanging flowers are usually short-lived tropical annuals that bloom like crazy until the approaching winter cold kills them. You can’t keep them alive without moving to South America. But you can help them bloom better by watering their container every day in the summer and pinching off dead flowers before they go to seed. Or just shear back each plant by 50 percent after flowering slows to stimulate production of new buds. Give them a weak dose of liquid fertilizer every three weeks, too.

Q. I have a concrete wall around a courtyard and am thinking about putting a plant like ivy in front of it to cover it up. Thoughts?

DARLENE HARRIER, Roxbury

A. Ivy sounds like a good solution — except it’s not. Like most vines, it can turn into an uncontrollable monster in a few years. Never plant ivy anywhere, and be wary of most other supposedly decorative vines except clematis. I think shrubs are lower maintenance. Just one kind of shrub planted along a wall looks architectural, while a mix of species looks like a garden. You’ll need tall upright-growing shrubs that like full sun and heat and don’t need much watering. You can visit the University of Illinois Extension website (extension.illinois.edu) and go to the questionnaire “Selecting Shrubs for Your Home’’ to find a good fit. For your conditions, they recommend native Viburnum dentatum, which provides food for birds. I like flowers, so I would recommend a hedge of mixed lilacs that grow to a more or less even height. Bonus: All lilacs can be cut for deliciously fragrant bouquets. ‘Lavender Lady,’ candy pink ‘Maiden’s blush,’ ‘Angel White,’ wine-red ‘Congo,’ ‘pale-pink ‘Beauty of Moscow,’ light-blue ‘President Grevy,’ blue ‘President Lincoln,’ and white-and-purple ‘Sensation’ are all favorites that grow to about 10 feet and can be planted in a row 5 feet apart. King’s Tree Farm & Nursery in West Boxford (978-352-6369, www.kingstreefarmandnursery.com) has more than 40 kinds of lilacs. You can see many in bloom if you shop in mid-May. (And the Arnold Arboretum’s famous lilac collection is a must-see on Mother’s Day.)

You could also consider a hedge of rose of Sharon, one of the few shrubs blooming in August. The new Chiffon series with pastel double powder puffs and the Satin series with old-fashioned hollyhock flowers both offer four color options on tree-like shrubs that eventually reach 10 by 6 feet. They have no scent, and each flower lasts just one day and then drops off. But these improved rose of Sharons are an increasingly popular summer alternative to hydrangeas because they withstand blazing sun, heat, drought, and pollution. Remember, though, that all shrubs need weekly watering their first two summers to get established. The best time to plant is in May or September.

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