June Gardening Tips and Tasks

• Take part in Pollinator Week! This is an annual celebration of the importance of pollinators and the many ways we can support them in our gardens and landscapes. Look for local events and consider participating in the National Pollinator Week Bioblitz through iNaturalist.
• Reduce and compost food and yard waste. About one-third of all food produced never gets eaten. Food waste dumped in landfills generates climate-warming gases as it decomposes anaerobically (without oxygen).
• Weeds are easier to manage when they are young and small and when the soil is slightly moist. Hand-pull weeds or use other methods to manage weeds without chemicals.

Monitor newly-planted trees and shrubs for watering until they become established (after about 2 years from planting), especially in the summer and autumn. When needed, water deeply by allowing the water to soak into the soil directly underneath the branches around the root ball. Check the depth of water percolation into the soil by digging a small hole after watering. It should be moist about 6 inches down. A mulch layer 2 to 3 inches thick helps to retain soil moisture and suppress weeds that would compete with the desirable plants for moisture. Keep mulch away from the trunk or main stems; don't mound it up to the base of the plant.

• Perpetual spinach, Malabar spinach, leafy amaranths, waterleaf, sweet potato leaves, jute leaves, and Swiss chard are good heat heat-tolerant greens for Maryland. Learn about some climate-resilient crops in the Less Common Vegetables for a Home Garden page.
• Flea beetles are a serious pest of eggplant and also feed on potatoes, tomatoes, and members of the cabbage family. Row cover is an effective means of pest management but should be removed when plants flower to allow for bee pollination. Spraying plants with kaolin clay (an organic pesticide) creates a white-particle film that can minimize flea beetle feeding. You can also control flea beetles with organic insecticides like neem (which will require 2 to 4 applications) or spinosad (which can be toxic to bees until it dries on leaves).
• Young tomato plants may be exhibiting symptoms of various leaf spot diseases such as septoria and early blight. Remove badly-infected lower leaves, keep a thick biodegradable mulch around plants, irrigate at the base of the plants to avoid wetting leaves, and remove the lower 3 to 5 leaf branches to improve air circulation around the plants.
• The “June drop” of excessive immature fruits (especially for peaches) is a natural thinning phenomenon that is more pronounced where no manual thinning has been done. Hand-thin immature fruits on plum, peach, apple, and pear trees, leaving space (the width of one fruit) between the remaining fruits. Disease and insect problems, environmental stress, and lack of pollination or poor fertilization can also contribute to early fruit drop. Pick up and discard all dropped fruits so they do not attract pests or harbor diseases.

• Cut iris flower stalks down to the crown when they are finished blooming, but leave the foliage alone. If iris are overcrowded after flowering, lift and divide them. Check rhizomes for iris borer.
• Warm-season annual flowers like zinnias, sunflowers, and cosmos can still be started from seed at this time.

Beneficial insects

• Skippers are active. This group of butterflies (distinguished by their hook-tipped antennae and rapid, skipping flight) is a part of our pollinator community. Some skipper caterpillar species rely on grasses for food. Consider planting a native grass like little bluestem (Schizachyrium scoparium) amongst a diversity of flowering pollinator plants to support all life stages. This will mean tolerating some chewing damage from caterpillars.
• Great spangled fritillaries are active. Support this native butterfly and other wildlife by recognizing and conserving native violets like the common blue violet (Viola sororia).
• Sphinx moths are becoming more active and are day and night pollinators, depending on the species. When creating pollinator gardens, incorporate night blooming plant species like common evening primrose (Oenothera biennis).
• Margined soldier beetle adults are active, aiding in pollination while they feed on pollen, nectar, and soft-bodied pests. Recognize and leave these beetles alone for their beneficial services. Incorporate a diversity of flowering plants to support these pollinating and predatory insects.
• Bee-like flower scarab beetle adults are active and found on a wide range of flowers, consuming pollen, leaves, and flowers. Many of our native plants (like magnolias) have co-evolved over thousands of years with these beetle pollinators and can tolerate this minor feeding damage. Leave these beetles alone when you see them, and consider supporting their populations by adding a diversity of plants with cup-like flower shapes like pawpaw (Asimina triloba) or dome-shaped flower clusters like New Jersey tea (Ceanothus americanus).

Pests

• Spotted lanternfly (SLF) nymphs (juveniles) are hatching and will grow through four life stages (instars) through July. Learn what their different life stages look like. Report any SLF egg hatch / early nymph sightings to the Maryland Department of Agriculture. If SLF eggs or nymphs are found in high numbers, the recommended control approach is to destroy the SLF physically. SLF does not harm landscape or garden plants enough to justify the risks of using pesticides that could harm beneficial insects.
• Wasps are becoming more active. Maryland is home to over one thousand wasp species, and the vast majority of them are not aggressive or defensive of a nest (in fact, many species are solitary). Identify a wasp before considering it a pest, and be mindful of social wasps constructing a nest in buildings and high-traffic areas. Leave nests alone when you can, and contact a professional pest control company for any nest removals. Avoid using any home remedies.
• Scale insects are best controlled during their vulnerable crawler stage (newly-hatched juveniles). Some species of scale, like cottony camellia scale, will begin hatching this time of year. Monitor for crawlers, particularly on plants with a history of scale infestation. Specific control methods and their timing are based on the scale species.
• Aphids are becoming more abundant. Allow local predators like ladybugs and parasitic wasps to control them. Avoid high-nitrogen, quick-releasing fertilizers, as studies have shown they can boost aphid populations. Horticulture oil can be used on heavy aphid infestations.
• Japanese beetle adults are active. Brush adults into a bucket of soapy water held underneath foliage or branches. Japanese beetle traps are not recommended; studies show that traps can attract more adult beetles to your landscape before they are captured, resulting in increased plant damage.
• Boxwood leafminer larvae (juveniles) are hatching within boxwood leaves and will begin to feed (chew "mines") within the leaf. Infested branches can be pruned out and disposed of. For chemical options to manage heavy infestations, contact a professional pest control company, since some insecticide ingredients can only be applied by a licensed pesticide applicator.
• Bagworm larvae are hatching this month and constructing silken bags which hide the caterpillars. Look for little bags moving around on evergreen trees and shrubs, and be prepared to spray infested trees with the biopesticide Bacillus thuringiensis (Bt) between now and mid-July, following all product label instructions. Bt does not work well on older caterpillars, so it's important to catch an infestation early.
• Mosquitoes are becoming more active and abundant. Patrol the yard for mosquito breeding sites. At least twice a week, check and remove water that may be collecting in trash and recycling cans or lids, flower pot saucers, child and pet toys, wading pools, tires, tarps, or plastic sheeting. Reconsider mosquito sprays/fogs that can harm beneficial insects. Fans can be used to deter mosquitoes from outdoor porches, since mosquitoes are poor fliers when faced with a stiff breeze.
• Ticks are becoming more active and can carry serious diseases that affect humans and pets. Wear light-colored long pants, long sleeves, and close-toed shoes. Tuck pants into socks, and tuck shirts into pants. Use insect repellents (age-dependent, check the product label for safe use), always AFTER putting on sunscreen. Shower and check people and pets for ticks after being outdoors.
• Squash bug adults are active. Place row cover over any cucurbit host plants to exclude adults and prevent egg-laying. Monitor plants for adults, eggs, and nymphs (juveniles). Adults are great at hiding under leaves and mulch. Leaves with egg clusters can be removed or the eggs squished.
• Squash vine borer adult moths are active. Wait to plant squash seeds until mid-June to avoid adult moth egg-laying. Cover squash plants with row cover until they flower, then lift the cover when plants bloom to allow for pollination. A "collar" of aluminum foil can be wrapped around lower squash stems to prevent egg-laying.
• Cabbage looper and imported cabbageworm caterpillars and the adults (a moth and a butterfly, respectively) are active. Check host plant leaves (mainly crucifers/brassicas) for signs of feeding damage and for the presence of caterpillars and droppings (frass). Caterpillars can be removed and destroyed. The biopesticide Bacillus thuringiensis (Bt) or neem oil can be used with heavy infestations, following all product label instructions.

Apple scab and a number of rust diseases (cedar-apple, cedar-quince, cedar-hawthorn, Japanese apple, and pear trellis rust) are destructive diseases of crabapple in the landscape. They cause severe leaf defoliation by midsummer if not treated. The best defense is replacing disease-prone cultivars with resistant selections available at garden centers.

Monitor houseplants for mealybugs, spider mites, aphids, whitefly, and scale insects. If houseplant pests are a problem, consider spraying with a labeled horticultural oil or insecticidal soap. If possible, move the plants outside before spraying; when dry, move them back indoors. Discard heavily-infested plants because high pest populations can be hard to eradicate and badly-weakened plants may not recover.

• Pantry pests, like Indian meal moths, grain beetles, cigarette beetles, and carpet beetles may be found around windows trying to get out of the home. These pests can be swept up or vacuumed; no chemical controls are recommended.
• Other unexpected indoor pests, like wasps or other species of moths or beetles, can be carefully relocated outside or vacuumed. Many night-active outdoor insects are attracted to light in the evenings. Consider reducing or turning off outdoor lights and reducing indoor light leakage by using blinds or curtains over windows so these outdoor insects are less likely to get inside. Check for openings or cracks in walls or around windows, torn window screening, and worn door weather-stripping to prevent entry points for insects and other pests.