June Gardening Tips

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Annuals and Perennials

  • Scout for lace bugs and aphids. Spray with water or use a low toxicity insecticide to control them.
  • Check container plants daily during hot weather: they will need water often.
  • Cut back early-flowering perennials to tidy up and encourage more blooms.
  • All plants, especially newly planted ones, need 1” of water per week. Water deeply and thoroughly as needed.
  • Keep on top of weeds during the early summer when they are small and easy to pull. If you keep your garden plants well-watered and fertilized, they will quickly fill in bare spaces and give weeds fewer places to grow.
  • To move spring-blooming bulbs to another spot, wait until the foliage has turned yellow, carefully dig them up and replant or let them dry in a shady spot for a few days, store in a cool, dry place and replant in fall. Make sure to check occasionally that they are not rotting or drying out.
  • Clematis varieties that bloom only in spring can be pruned back and they may produce a second flush of growth and flowers. Or just lightly prune just to shape and to remove damaged and wayward stems. Leave the decorative seed heads. Check which pruning group the clematis you have is in.
  • Sow seeds of fast-growing annuals like marigolds, zinnias, and cosmos directly in the garden.
  • Plant summer-flowering bulbs such as cannas, gladiolas and dahlias.
  • Plant caladium and tuberous begonias in shady spots. Bulbs should have been started indoors in March
  • Lightly cultivate soil after a heavy rain to avoid compaction. A layer of mulch reduces the soil crusting and compaction caused by raindrops.
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Education and Events

Houseplants

  • You can move houseplants outside to the deck or patio and enjoy them outdoors for the summer. It is best to gradually introduce them to more direct sunlight to prevent the leaves from being burned.
  • Be aware that container plants will need more water during hot and windy weather.
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In the Vegetable Garden

  • If Tomato plants are leggy, plant deep and they will root along the buried stems.
  • Stake or cage tomatoes and spray them if necessary to prevent disease problems.
  • Check for small holes that signal flea beetle damage on tomatoes, eggplants and peppers.
  • Call the UConn Home & Garden Education Center (877) 486-6271 or email us at ladybug@uconn.edu  if you suspect tomato disease problems.
  • There is still time to sow seeds of beans, beets, carrots, cucumbers, and summer squash.
  • Plant seeds of bush beans every three weeks for a continuous harvest.
  • For the sweetest pea harvest, pick regularly before pods become over-mature and peas become starchy.  
  • If you must overhead water do so early enough in the day to allow the foliage to dry before nightfall to minimize diseases.
  • Plant vegetables or flowers in unadorned pots or decorative jardinieres and grow them on decks or patios if space is limited.
  • Harvest early season vegetables including lettuce, radishes and peas when they are at their peak.
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Insects

  • Heavy rains encourage slug problems. Check for slugs during rainy periods and hand pick the pests.
  • Scout for lace bugs and aphids. Spray with water or use a low-toxicity insecticide to control them.
  • Check for small holes that signal flea beetle damage on tomatoes, eggplants and peppers.
  • Check apple, cherry, and other fruit trees for nests of Eastern tent caterpillars. Blast low-lying nests with water to destroy them, or knock them to the ground and destroy them. A spray of Bacillus thuringiensis on the foliage will kill emerging caterpillars after they consume it but is not toxic to beneficial insects, birds, or humans.
  • Apply grub control after June 15th if grub damage is noticed or was a problem last year. 
  • Scout for black vine weevil adults feeding on azalea and rhododendron foliage and use a foliar insecticide.
  • June bugs, can be annoying as they bounce on your window screens attracted by your house lights. The larvae do eat plant roots and the adult beetles forage on trees and shrubs although they do not seem to cause the excessive damage associated with Oriental beetles or Japanese beetles.
  • Mosquitoes breed in standing water. To discourage them, change the water in bird baths and outdoor pet dishes every few days.
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Landscape and Lawns

  • Heavy rains encourage slug problems. Check for slugs during rainy periods and hand pick the pests.
  • Scout for lace bugs and aphids. Spray with water or use a low-toxicity insecticide to control them.
  • Check for small holes that signal flea beetle damage on tomatoes, eggplants and peppers.
  • Check apple, cherry, and other fruit trees for nests of Eastern tent caterpillars. Blast low-lying nests with water to destroy them, or knock them to the ground and destroy them. A spray of Bacillus thuringiensis on the foliage will kill emerging caterpillars after they consume it but is not toxic to beneficial insects, birds, or humans.
  • Apply grub control after June 15th if grub damage is noticed or was a problem last year.
  • Scout for black vine weevil adults feeding on azalea and rhododendron foliage and use a foliar insecticide.
  • June bugs, can be annoying as they bounce on your window screens attracted by your house lights. The larvae do eat plant roots and the adult beetles forage on trees and shrubs although they do not seem to cause the excessive damage associated with Oriental beetles or Japanese beetles.
  • Mosquitoes breed in standing water. To discourage them, change the water in bird baths and outdoor pet dishes every few days.

Landscape and Lawns

Fruits

  • Check apple, cherry, and other fruit trees for nests of Eastern tent caterpillars. Blast low-lying nests with water to destroy them, or knock them to the ground and destroy them. A spray of Bacillus thuringiensis on the foliage will kill emerging caterpillars after they consume it but is not toxic to beneficial insects, birds, or humans.
  • It's a great time to plant strawberriesblueberries, raspberries, and blackberries.
  • Harvest early season fruits such as strawberries when they are at their peak.

Lawns

  • Keep mower blades sharp and set your mower height at 2-3 inches.
  • Mow lawns often enough to remove no more than one-third the total height per mowing. There is no need to remove clippings unless excessive or diseased.
  • Grass can quickly invade gardens and landscape plantings and is best deterred with a good quality edging that is properly installed.
  • Leave grass clippings on the lawn to improve availability of nitrogen.
  • Apply grub control after June 15th if necessary.

Trees and Shrubs

  • Scout for black vine weevil adults feeding on azalea and rhododendron foliage and use a foliar insecticide.
  • Overgrown, multi-stemmed shrubs like spirea, lilac, and forsythia, can be renovated by removing 1/3 of stems down to ground level each year for 3 years, allowing some new young growth to replace these older stems.
  • When deadheading rhododendrons, avoid breaking off the leaf buds which are just below flowers. Carefully twist off spent blooms.
  • Gator bags provide a great way to keep trees watered during hot and dry months. These bags, which can hold up to 20 gallons of water, are secured to the trunk of the tree, where they release the water slowly to the root ball over the course of 15 to 20 hours.
  • June bugs can be annoying as they bounce on your window screens attracted by your house lights. The larvae do eat plant roots and the adult beetles forage on trees and shrubs although they do not seem to cause the excessive damage associated with Oriental beetles or Japanese beetles.
  • Watch for and control blackspot and powdery mildew on rose foliage.
  • This is a good time to take cuttings of trees and shrubs, such as chokeberry, butterfly bush, spirea, serviceberry, hydrangea, dogwood, and magnolia, to root for new plantings.

Wildlife

Yard Accessories and Miscellanea

  • Mosquitoes breed in standing water. To discourage them, change the water in bird baths and outdoor pet dishes every few days.
  • Add to aerate, and moisten compost pile to speed decomposition.
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Despite good cultural practices, pests and diseases at times may appear. Chemical control should be used only after all other methods have failed.

For pesticide information please call UConn Home and Garden Education Center weekdays, in Connecticut call toll free 877-486-6271. Out of state call 860-486-6271

Revised by the UConn Home and Garden Education Center 2017

Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, the Dean of the College, Cooperative Extension System, University of Connecticut, Storrs. The Connecticut Cooperative Extension System is an equal opportunity employer and program provider. To file a complaint of discrimination, write USDA, Director, Office of Civil Rights, Room 326-W, Whitten Building, Stop Code 9410, 1400 Independence Avenue, SW, Washington, DC 20250-9410 or call (202) 720-5964.