Garden Notes

Island bouquet of color

'Excelsa' rambler rose
A 'Excelsa' rambler rose. Photos by Susan Safford

By Abigail Higgins - July 5, 2007

The end of June closes the majestic parade of showy late spring perennials - iris, peonies and poppies - but segues the garden into daylily time. The quintessential Vineyard bouquet is the clashing fistful of flowers comprised of 'Excelsa' rambler roses, perennial sweet pea, and the tawny daylily picked by Island children for generations. Red, white, and blue may be the colors of the patriotic holiday, but the mason jar of wayside flowers on the picnic table is orange, magenta, and cerise.

The Island has had the first spike of hot, humid air: summer is here and there has been no appreciable rain for the past several weeks. Molds, leaf spots and other foliar diseases, deer, snails and slugs - all these are to be expected now. Remember to water the soil, not the plant. Water early in the day, when possible, to give all parts of the plants the best chance to dry fully, especially in the case of plants such as strawberries. In some of the gardens we work in, we are doing last-minute, down-to-the -wire pinching and staking. (In a perfect world, all this would have been accomplished by early June.)

Water is best

Plants in containers and hanging baskets and pots in particular are having a harder time getting through the day and week without increased watering sessions in these hot days. Not only is there dryness to contend with but also heat, the two of which are easily confused when one sees flagging leaves. If it is not too large, lift or tip the pot to gauge whether it has a light feel; container soil that holds water and is moist has a certain heft. Once plants have become parched and totally wilted, they are much more likely to be visited by foliar problems such as powdery mildew.

Deadleaf daylilies and give them a side dressing of compost or fertilizer if you want the heavy-feeding plants, hybrids especially, to do their best. Flowers on some tetraploids are so large and buds so numerous on the scape, that removing the passé flowers is really essential for best appearance. Deer spray is a good precaution too.

A tawny daylily
A tawny daylily

Kousa dogwoods are in bloom. Ours usually lights up our bedroom in a slightly bizarre 6 am way when the early morning sunlight strikes and reflects from its profusion of creamy bracts. Not this year, thanks to extensive caterpillar feeding. Mulch trees with a drip-line circle of compost for good growth, but keep the mulch away from the trunk. In the caterpillar areas, water them - this applies to all stricken specimen trees - to nurse them into re-leafing. At the Polly Hill Arboretum, Paul Cappiello will talk on small ornamental trees, including dogwoods, Wednesday, July 11, and lead a guided tour of those in the PHA collection the next day. Please call 508-693-9426 for more information.

In the vegetable garden, rocambole garlic is heading up. Remove the curlicue scapes by cutting them out; this is done to improve bulb size. Most gardeners compost them, but some people add the curling ends to Asian style stir-fries. Lettuce and other quick-growing greens such as spinach, arugula, and mustard greens bolt quickly now. New crops need frequent sowing, then thinning, to keep the supply coming.

Thyme is flowering; trim off the flowering heads to keep the plant producing plenty of new leaves. Cut chives down or pull the stalks of gone-by flower heads. They are heavily laden with small black seeds that self-sow and sprout easily. Careful growers spray cole crops against the European cabbage white butterfly weekly with Bacillus thuringiensis (Bt). Continue to pinch out the side shoots of tomatoes and tie in to supports.

Easy on the grass

Un-irrigated lawns are becoming crispy, so it is important to increase the cutting height of the mower blade. Setting the blade higher allows the longer grass leaves to better sustain the whole plant by growing longer roots.

The following information comes from the University of Massachusetts Landscape Message:

"Cape Cod Region (Barnstable) - General Conditions: Lovely summer weather for the beach-goers, but landscape soils are very dry. We have had no significant precipitation for several weeks now, and plants that are not irrigated are starting to look dull. Hydrangeas are beginning to color up. Pests/Problems: Japanese beetles should be emerging within the next week or so. Aphids are plentiful on roses. Lily leaf beetle larvae are in the fourth instar. Ants are active in sandy soils of scalpedturf. Pitch tubes of black turpentine beetle are visible. It is too late to treat at this point.

"Southeast Region (Hanson) - General Conditions: Hot, hot, hot and humid. Hanson received 0.45 inches of rain, not enough to make a difference, and soils are dry. Remind clients to water plants that were planted this season and also trees that may have been defoliated the past few years. Spirea, tuliptree, kousa dogwood, Deutzia sp., Rosa rugosa, clematis, roses, Astilbe sp., Corydalis lutea, foxgloves, lavender, Lamium, Aruncus, Persicaria polymorpha, Dicentra eximia, Geranium sp., Dianthus, Nepeta, salvia, 'Stella d'Oro' and other early daylilies are in full bloom. Pests/Problems: Asiatic garden beetles, cutworms, earwigs, pieris or andromeda lacebug, aphids, cottony taxus (camellia) scale on holly and taxus, fruitworms, carpenter bees, dog ticks, deer ticks, leafhoppers, lily leaf beetles, slugs, snails, mosquitoes, wasps, and ladybugs are all active. Four-lined plant bug damage has been observed. Powdery mildew is showing up on susceptible Phlox paniculata. Monitor flowering dogwoods for dogwood anthracnose. Apple scab is evident on susceptible apple and crabapple foliage, azalea leaf gall (Exobasidium vaccinii) is showing up on deciduous azaleas. Weeds of all sorts, including crabgrass, are numerous. Clover is in full bloom...."

Trying to find out more on the subject of azalea leaf gall on the Cornell University plant diagnostic web site, I learned that these pale green disfiguring growths are called "pinkster apples" and are considered a food delicacy by some! Whether for control or culinary purposes, in the home garden they can be picked or cut by hand early in the season when they first appear. Destroy by burning or burying in the ground. For larger plantings, control with basic copper sulphate, spraying the entire plant.