Plants and people love the long days of summer and June has the most. The 21st is the longest. The summer solstice. Mid-summer’s day.

With our average frost free date a month behind us, we can now plant even the most tender plants outdoors. If you’ve been cautious or just haven’t gotten around to it, this is a good time to plant tomatoes, peppers, eggplant, basil, plus impatiens, begonias, and coleus. You can still sow seed for marigolds, cosmos, four o’clocks, zinnias, and sunflowers. Sow seeds for cucumbers, beans, and summer squash, too.

Drag out the houseplants. Put them in a shady spot where it is still brighter than your family room. The lower light all summer means the transition back inside in the fall won’t be too drastic for them either.

Fertilize the lawn. Mulch the flower border and vegetable garden. Keep on top of the weeding, watering and lawn mowing.

Do a sketch of the basic layout of your property in bird’s-eye view. Identify the locations of only the primary plants such as trees, shrubs and large clumps of perennial flowers. Make some copies and then each week, use one to makes notes of what is flowering where and what colors they are. Then you will be able to select new flowers to add for continuous flowering next year.

June is also when problems start to arise. Get help from the UW-Extension Horticulture Helplines in Milwaukee, Waukesha, Racine and Kenosha Counties. Another alternative is the UW-Extension Horticulture Center at Boerner Botanical Gardens in Whitnall Park in Hales Corners. Drop-in just for the personal service or as part of a visit to the Gardens. Hours are Monday through Friday from 10:00 until 2:00.

Join me for a JSOnline chat on the first Tuesday of every month at http://www2.jsonline.com/chat/. You can also check out the answers to questions from previous sessions in the archives. Yours might have already been answered for someone else.

Visit the UW-Extension’s Horticulture Team website at http://wihort.uwex.edu . You'll find factsheets, articles and lots of links to other great gardening-related sites.

More detailed information about many of the garden calendar entries is available through the UW-Extension InfoSource. Use the three-digit number provided after an entry to read more on that topic. Go to http://infosource.uwex.edu then enter the message number in the search box.
 

First Week

June 1st is considered to be safe to transplant tomatoes to the garden. Plants with spindly stems can be buried in a trench up to their first set of true leaves.

Don't fertilize tomatoes until the first fruit has set. Too much nitrogen will cause leafy growth at the expense of flowers and fruit. Most other plants benefit from a starter fertilizer when transplanted.

June 1st is also when your first lawn fertilizer application should be made. If you fertilized earlier this spring, wait until Labor Day or Halloween to do it again. However, if you routinely water your lawn all summer long, another light application may be needed in July.
 

It is too late for broadleaf weed control products or combination weed 'n feeds. Summer's heat will cause the weed killer to vaporize and drift, damaging other flowers & vegetables. Total vegetation killers such as glyphosate can be used all season but will kill everything so don’t use them in your lawn or allow overspray onto desirable plants.
 

Fertilize bulbs and most perennial flowers now. Bulbs are forming next year’s flowers inside and perennials are actively growing and producing flowers.

Prune, transplant and up-pot houseplants since they will be growing most vigorously now due to the longer days, higher light, and warmer temperatures. Move up to a pot only one or two inches larger at a time. Fertilize monthly.
 

Houseplants really benefit from a summer vacation in a shady spot in the yard. Even those that prefer very bright light should be in the shade. Surprisingly, outdoor shade is still brighter than almost any spot indoors. Plus the move back into the house in the fall will be less traumatic.

Prune out and destroy webs of Eastern tent caterpillar found wrapped around branches of fruit trees including crabapples. The biological control sold as Dipel, Bactur, or Thuricide is only effective while the caterpillars are still small. Soon they will move off the trees to pupate. Destroy these pale yellow, loosely constructed cocoons. In August look for shiny brown egg masses on tree branches. Prune them out or scrape them off.
 

Examine honeylocust and ash foliage for plant bugs. Control with insecticidal soap sprays as needed.
      

Preventative insect control for fruit bearing trees should have been started at petal fall. Continue every 10-14 days until autumn leaf drop.


Preventative treatment for apple scab and rust diseases should have been started before bloom started. For crabapples, collecting and destroying fallen leaves all season combined with proper watering and a fall fertilizer application may be all that is really necessary since these diseases are not life threatening.
      

There are many insect pests to watch for in the vegetable garden now. UW-Extension publication A2088 “Managing Insects in the Home Vegetable Garden” provides greater detail. The following are pests in Wisconsin:
   

The flea beetle chews many small holes in the leaves of a wide range of vegetable crops especially young transplants of the cole crops (broccoli, cauliflower, cabbage, and Brussels sprouts). Cover with floating row cover to exclude these tiny, hopping bugs before they begin feeding. This covering can be left in place day and night since it is permeable to light and moisture. It also "breathes" so that heat does not build-up underneath. Be sure to seal the lower edges with soil or stones. Allow ample room underneath for plant growth.

Covering cole crop plants with floating row cover will also exclude egg laying by the cabbage moths.
 

Potato leafhoppers are wedge-shaped, bright green insects that cause "hopperburn" on plant leaves beginning in early June. Spray once with carbaryl or malathion and cover the entire crop with row cover to prevent invasion.

Colorado potato beetle adults and larvae can be hand picked to remove or sprayed with M-Trak, a biological control product. Adults are yellow and black striped beetles and the larvae are humpbacked and red. Look for them on the stem tips. They are present
almost all season.

Striped and spotted cucumber beetles transmit a bacterial wilt to cucumbers, squashes, and melons. Adults and eggs can be hand picked throughout the season or begin preventative sprays or dusts with rotenone or carbaryl as soon as seedlings emerge. Leaves of infected plants wilt only during the day but the leaf stems remain erect. Eventually, the entire plant wilts and dies.
 

Watch for Mexican bean beetle which descended on vegetable gardens a couple of years ago but have since subsided. To be on the safe side you can cover the entire crop with floating row cover as soon as seedlings emerge. Spray with carbaryl or rotenone at the first sign of beetles or their distinctive feeding damage.

No further pruning should be done on trees or shrubs since the new growth this
stimulates will not mature sufficiently before the cold days of winter are again upon us.

 

Second Week

Aphids of all types show up on a range of host plants as soon as the warm weather arrives. Look for them in newly unfurling foliage, which may be curled downward around aphid colonies. Sticky leaves are also a sign of their presence since they secrete "honeydew". Black sooty mold may also grow in this sticky substance but it does little damage since it does not penetrate the leaves. Aphids, however, do damage the plant. Spray leaves with a strong jet of water to dislodge some of them. Insecticidal soap is a low-toxicity product that provides pretty good control as long as the insects are wetted thoroughly. A second and third treatment to kill newly hatched eggs may be needed in 5 - 7 days.

Check spruce and arborvitae growing in hot, dry sites for spider mites. Tap a branch several times on a piece of white paper and then hold it very still for about 30 seconds. Mites will appear as tiny, moving black specks. If present, thoroughly wet plants with a blast of water from the hose. Repeat until no mites are found.
 

Continue mowing around ripening foliage of spring flowering bulb plants growing in the lawn. For best flower bud development and vigorous growth next year, allow leaves to yellow completely before removing.


 

Third Week

Once the soil has warmed, put a 2 – 4 inch layer of organic mulch on flowerbeds and around trees and shrubs. Good mulches include shredded bark, woodchips and chipped yard waste often available from your municipality. Mulch discourages weed growth, holds in soil moisture and maintains even soil temperatures. Around trees, it may simply serve to help prevent “mower damage” to trunks. Better yet expand the mulch ring to include the entire root zone or at least out to the “drip line”. Spruces and birches really benefit from this to reduce drought stress and resulting disease and insect problems.

Squash vine borer adults are 1 inch long orange and green day flying moths that are emerging from the soil now. They lay brown, button-shaped, 1/16 inch eggs at the base of the vines of summer and winter squashes. Examine stems daily and remove eggs by hand to prevent burrowing of larvae as they hatch. Wrap lower 6 – 12 inches of stem with aluminum foil or floating row cover to prevent egg laying. Stem bases can be sprayed with carbaryl weekly for three weeks. The liquid seems to be more effective than dust.
 

Red sphere traps coated with Tanglefoot can be hung in apple trees now to control apple maggots. Use 1 trap per 100 apples expected.

Renovate June-bearing strawberry plantings immediately after harvest. Control any weeds that have invaded and then mow over the top with the mower set high enough not to damage the crowns. Eliminate new plants between the rows by cultivating. Then sidedress with a 10-10-10 fertilizer. Lightly work it into the soil and water in.
 
 

Fourth Week

Newly established plantings of raspberries can be fertilized now with 2 -3 pounds of ammonium nitrate.

Fertilize roses after the first flush of blooms. Use one tablespoon of a complete, low nitrogen fertilizer per plant.
 

Oak, elm, and maples with one of the wilt diseases will begin to show typical wilting symptoms as the summer heats up. Watch particularly the upper crown for branches with wilted leaves. Call your county UW-Extension to assist with diagnosis at the first signs of wilt.
(oak)    (elm)     (maple) 

Pinch back garden chrysanthemums one last time. Flower buds will form on new growth and be ready for fall display.