Tidewater Gardening - June 2010


Early Summer Gardening Chores
K. Marc Teffeau


June is a busy time for home gardeners. You’ve probably got most of your vegetables in by now, and most of your annuals are planted. But there are still a number of chores awaiting you in both the vegetable and flower gardens.
After they have finished flowering, German iris can be divided and replanted. Cut back the leaves about a third and divide the clumps into single plants with one or two sections of healthy rhizome. Discard any diseased plants with mushy rhizomes. If disease has been a problem with your iris, it may be wise to try a new location for them. To control the iris borer, apply a systemic insecticide to the fans.
Dutch irises, sometimes call the “year round iris” because of it’s availability as a cut flower, is also a great garden performer. Dutch irises are hybrids whose parentage can include many species. The garden variety Dutch irises bloom much later than the earlier spring-flowering dwarf iris, and add rich color to the “transition” garden. It is safe to say they are not used nearly often enough in the landscape. Reaching around two feet tall, they should now be showering well-planned gardens with their blue, yellow, white, deep purple and now some two-color blossoms.
After blooming has finished for the season, leave the foliage in place; don’t cut it off. The leaves will gather sunlight and provide nourishment for next year’s show. Water as needed during active growth periods. Dutch irises actually prefer not to be watered while dormant. At the end of the summer the leaves will yellow and die back as the plant slips into dormancy. Foliage many be removed at this point. Your iris will rest for a few months before beginning the next growing cycle.
While you are working with your perennials don’t forget to divide spring and early summer flowering perennials such as lilies after the blooms fade. Instead of severing the clump in half, try jiggling the roots apart with two sharp, spading forks. This takes more time, but damages fewer roots than cutting the clump apart. Delphiniums bloom this month. To encourage more flowers, feed the plants after bloom, cut back spent stalks to one foot and then remove stalks entirely when new growth is about six inches tall. Unless you like leaning delphiniums, be sure to stake them before they grow too tall.
If you haven’t done it yet, remove all old flower heads from your rhododendrons and lilacs. The lower heads of the rhododendron are best broken out by hand. Do this now to increase growth and the development of flower buds for next year. I recommend pruning out the spent lilac flower heads rather than breaking them out.
Although the mulching sales frenzy occurred earlier in the spring, by late June the fertile environment you’ve created with the attentive feeding and watering has been good for all the plants in your garden – including weeds. Weeds are the number one garden problem in early summer.
The onset of warmer weather and more direct sunlight is a signal to add mulch. Mulching greatly aids in the control of weeds in flower and shrub beds. Even if you haven’t mulched your plants, it’s not too late. You’ll have to clean up plant beds first, though. If you hoe out the weeds, be sure not to cultivate too deeply around shallow-rooted plants. Azaleas and boxwood are two shrubs especially vulnerable to careless cultivation. Apply a pine or hardwood bark mulch no deeper than two inches.
Trim back vines (spring-blooming clematis and wisteria) after they bloom. Prune back the tops of the plants to force out new branches. Gardeners are sometimes confused about proper pruning of their wisteria vines. The two species most commonly grown are Wisteria floribunda (Japanese wisteria) and Wisteria sinensis (Chinese wisteria), both of which bloom before or with the unfolding of the leaves.
Pruning wisteria extensively during the dormant season may encourage rampant vegetative growth the next spring. Instead, in June prune out the long, straggly growth except those branches needed for climbing. This is more likely than anything else to induce flowering.
Shoots should be cut back one-third to one-half their length. This will induce them to produce the short spurs that will bear next season’s flower clusters. Wisterias are normally vines, but pruning can make them take shrubby and/or weeping forms. Heading back young shoots holds the height at a definite point and after several years, the plant produces a trunk-like stem. Leaders then can be allowed to droop to the ground.
When the foliage of the spring flowering bulbs yellow, it is time to clean it up. After cleaning up the bulb bed, add your next stage of summer color by setting out bedding plants to cover the bare spots taking care not to damage bulbs. When your early, annual flowers are spent, replace them with summer annuals, such as nicotiana, portulaca, zinnia, impatiens, or celosia. Before planting, rework and enrich the soil with compost.
Now is the time to be on the lookout for the Bagworm. This insect, scourge of cedar trees and other narrow-leafed evergreens, hatches out around the first of June. Each little “Christmas ornament” hanging on your cedar tree, if it had contained a female Bagworm, now contains between 200 and 1000 eggs ready to hatch when the temperatures are correct. Bagworms are best controlled as soon as they hatch as the older and bigger they get, the harder they are to control with insecticides.
The best “organic” control method for this pest is hand picking and destroying the bags before June 1st. For the bags you can’t reach and remove, treat with an insecticide. Early in the hatch, spraying the plant with Bt or Bacillus thuringiensis is the best control. Sold under the trade names of Dipel, Bt or Biotrol, this naturally occurring bacterium is effective for caterpillars in the early stages of growth.
If you are growing chrysanthemums, June is the time to disbud the flowers if you want to secure large, beautiful blooms on straight, strong stems. To disbud, remove the small, side buds that form in the angles of the leaves along the stems. This allows all food reserves to be used for one large flower rather than many smaller ones.
It is still not too late to divide the chrysanthemum plants to produce more plants in the garden. Carefully lift the clumps and divide out the individual plants. Replant them in the landscape where you want to expand your planting. After transplanting, give the plants a watering with a liquid fertilizer at half strength to give them a little “kick” to get them over the transplanting shock. If they have gotten too tall they can be cut back by about one half now to reduce their fall height.
Consider doing some supplemental fertilizing in the vegetable garden. Precision placement of fertilizer in the row, near the root zone of vegetable plants, reduces fertilization costs, does not stimulate between-row weed growth, and may help reduce fertilizer contamination of run-off water. Side dressing, a technique to fertilize established vegetable crops, is beneficial for adding fertilizer when it is most needed by the crop.
If you would like to provide your vegetable plants an efficient and steady feeding of organic fertilizers, sink a large can or bucket with many holes in its sides into the soil and fill it about 2/3 full of rotted manure or compost. Rain or occasional watering will keep a rich supply of nutrients seeping out to feed plants in a circle several feet wide.
Cucumbers have a very short “vine storage time.” Under warm, humid conditions, fruits on the vine may remain in prime condition for less than 12 hours. For the best tasting cukes, pick early and often. The fruits can be stored for up to two weeks at 45° to 50° and 95% relative humidity. Lower temperatures cause chilling damage, and higher temperatures encourage yellowing. Yellowing is also accelerated if cucumbers are stored with tomatoes or apples.
Remove cucumbers from the vine by turning fruits parallel to the vine and giving a quick snap. This prevents vine damage and results in a clean break. If you have trouble mastering this, take a sharp knife to the garden for harvesting. Cut or pull cucumbers, leaving a short stem on each fruit.
Remember that the time of day vegetables are harvested can make a difference in their taste and texture. For sweetness, pick peas and corn late in the day. That’s when they contain the most sugar, especially if the day was cool and sunny. Other vegetables, such as lettuce and cucumbers, are crisper and tastier if you harvest them early in the morning before the day’s heat has a chance to wilt and shrivel them.
Yellow crook neck or straight neck squash tastes best when 4 to 7 inches long. Pick when pale yellow (rather than golden) and before the skin hardens. Scalloped (patty pan) squash is best when grayish or greenish white (before it turns ivory white) and is still small, even silver dollar size.
Happy Gardening!!