Ask the Gardener: Tour the most beautiful gardens, including mine
Plus, when it is safe to plant frost-sensitive annuals like impatiens, summer vegetables like tomatoes, and tender herbs like basil.
What to do this month: It’s the season for garden tours. I like to wear a white garden frock and a sun hat to these New England fund-raisers to complement the beautiful settings (Bike shorts just don’t look right!):
■ My own Milton garden will be on tour with six others on June 11 (rain date June 12) from 10 a.m. to 4 p.m. Tickets are $25, benefit Milton Cemetery and Arboretum, and are available at the site, 211 Centre St., or online at Eventbrite.
■ Graves Library’s Secret Gardens of Kennebunkport, Maine, will be open on July 16 from 10 a.m. to 3 p.m. (rain or shine). Tickets are $40 online via Eventbrite.
■ Visit gardenconservancy.org for information on The Garden Conservancy’s Open Days garden tours throughout New England, including Berkshire and Bristol counties on June 11 and the South Shore on June 18. Tours of each garden are $5 for members; $10 for general admission; and children 12 and under are free.
■ The Garden Club of Mount Desert Open Garden Day in Maine, on July 30 ($40), has perhaps the most spectacular gardens. Inquire at [email protected] or visit www.mainetravelmaven.com/maine-garden-tours for more information.
Q. In Zone 6b, at what dates can one plant perennials and annuals safely?
J.M., Belmont
A. It is now safe to plant frost-sensitive annuals like impatiens, summer vegetables like tomatoes, and tender herbs like basil. Perennials are by definition winter hardy, so you can plant them almost anytime the soil isn’t frozen, though the best months are April, May, September, and October partly because they get the most rain. The same is true of trees and other woody plants. By June 8, it is safe to plant anything, and it is also safe to move houseplants outdoors.
Q. Should peonies be cut back like the other perennials you mentioned a couple of weeks ago, specifically Montauk daisies and phlox? (“Ask the Gardener: Growing sunflowers to support Ukraine,’’ April 24) Peonies have a lot of buds right now, so would cutting some of them off result in more flowers?
J.C., Dover, N.H.
A. You can cut back tall fall bloomers such as New England asters now to make them shorter and bushier, but not spring and early summer flowers like peonies. If you pinch off peony side buds, you will get fewer but larger flowers. I set up peony hoops for each plant to grow up through in late April. Without staking, the heavy cabbage head flowers will bend or break if you water them while they are blooming. So don’t do it. If it rains, just harvest the bent ones for bouquets. Varieties with single petals usually don’t need staking but are not as fragrant.
Q. Two of my rhododendron bushes are starting to fail. The roots of the bushes became black, and the leaves started to die. Is there anything I can do to rehabilitate them? I have others at the opposite side of the garden bed that are the same age and thriving.
C.M., Manchester, N.H.
A. Rhododendrons are low-maintenance shrubs, but they need moisture when it’s dry. Water the root area deeply once a week, and cover it with 3 inches of bark mulch to help retain the moisture. When mulching any trees or shrubs, leave a mulch-free “doughnut hole’’ around the woody trunk to prevent rotting. Apply a fertilizer specifically for acid-loving plants each spring. Give rhododendrons extra water in October and November so their evergreen leaves can lock in moisture for the winter. Consider relocating rhododendrons that are exposed to winter winds that can dry out the evergreen leaves, turning them brown.
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