Ask the Gardener: Arborvitaes need this to flourish

Ask the Expert Gardening
Arborvitaes can serve as a privacy barrier with the proper care. Adobe Stock

What to do this week: Keep planting warm-weather vegetables such as tomatoes, plus flowering annuals and perennials, shrubs, and trees. But wait until September to put down grass seed. If you buy containers of those colorful annuals that fill the market, water them frequently because moisture evaporates from all sides. Move tropical potted plants into partial shade outdoors, and keep them watered, too. Stake floppy plants. Keep pulling flowering weeds before they go to seed. Bag them. Don’t contaminate your compost pile with seeds from blooming weeds. Never compost invasives such as bindweed, bittersweet, English ivy, ground ivy, witchgrass, or goutweed, which can spread by a bit of root.


Q. We planted about 10 10-to-12-foot-high arborvitaes in a row about two years ago. They are looking ragged with very sparse tops. What can I do to improve their robustness? Should I trim the top leader? Call a tree company to fertilize? Help!

C.E., Portsmouth, N.H.

A. Don’t touch the leader! That will deform the tree. Summer drought is the likely culprit. Forget the fertilizer and just water them deeply each week through August during their crucial first three summers of adjustment. Trees die from thirst, not hunger. People frequently put sun-loving plants such as arborvitaes in too much shade. If their yard isn’t dark as a solar eclipse, homeowners tend to overestimate the amount of sun they get. Arborvitaes lose fullness with less than four hours of direct sun daily. They need to cast a shadow on a sunny day. If this is the problem, reduce the shade by pruning the trees overhead or moving the arborvitaes to a sunnier location. Contact your landscaper about whether the trees are under warranty, and ask for restitution or a solution, including moving the trees while they are still young. If what you want is a privacy screen in a shady area, consider a traditional old-fashioned lilac hedge of purple Syringa vulgaris or its hybrids, which grow fast, tall, and narrow. They tolerate more shade than evergreens. They lose their leaves late in the fall and then leaf out again early in the spring, producing those fragrant flower trusses in May.


Q. I’’m looking for a person to help me with my garden and yard — maybe 10 hours a week. Do you have any recommendations on how to find this person?

D.S., Milton

A. It is an ongoing question for me and many other gardeners. I’m always asking people whether they can recommend garden help. When I find someone good, I am very grateful, but I don’t pass his or her name around. I used to, but then found I couldn’t get help when I needed it. Gardeners can help only a handful of clients, all of whom seem to want them at the same time — high spring and late fall. Anyway, a good gardener is never looking for more work. I have tried to train a number of folks myself, with mixed results, partly because a lot of people don’t have a feel for the difference between working with living plants and with inanimate objects. Avoid “mow and blow’’ teams trained only in lawn care and mulching if you are growing real gardens and not just trying to neaten a low maintenance landscape of lawn and ground covers. You can find landscape designers and landscapers who do major work like planting and pruning.


The Newport Flower Show re-creates the horticultural opulence of the Gilded Age on June 21-23. The front lawn of the Rosecliff mansion on Bellevue Avenue will become an aviary of both real birds and those made of plant materials to reflect this year’s Audubon theme. Visit for tickets ($20 in advance) or more information. It all benefits The Preservation Society of Newport County’s
landscape restoration efforts at its historic properties.

Roslindale Clean & Green will host its sixth annual tour of private gardens on Saturday, June 22, from 11 a.m. to 4 p.m. Visit for information or to purchase tickets, which are $20.

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