Your June Gardening Checklist

By Skip Richter, Contributing Editor

Vegetables and herbs

Warm-season vegetables are still in peak harvest this month in most of Texas. For best quality, harvest each one at its peak stage.

Don’t let green beans get too mature. Harvest them when they are just about to reach full size but not quite full size and they’ll be tender and tasty.

If your tomatoes are being bothered by birds or squirrels, you can harvest them when they are green but starting to get a blush on the fruit, and can let them ripen on the counter indoors. Sometimes these varmints will even go after them before this stage!

Warm-season vegetables like ‘First Lady II’ tomato are ripening now. Try to
harvest them at peak maturity for best flavor and quality.

Starting seeds in hot weather can be challenging as the soil really heats up and also dries out faster. Placing row covers over the row can help shade the soil a bit, slowing drying and moderating soil temperatures. It also keeps out some of the pests that will go after your tender emerging seedlings.

Continue planting summer vegetables. Our palate of summer options is more limited than spring and fall options, but you can still try something different this year. Some heat tolerant, non-traditional vegetables include vegetable amaranth, molokhia, water spinach (kankong), Malabar greens and purslane (‘Goldgelber’ is a vegetable variety.) You might find one that becomes a regular part of your summer garden. Although these veggies are heat tolerant, they’ll need moist soil to perform well.

As the temperature rises toward the end of this month and next month, some of the vegetables that were productive in early summer will start to decrease quantity and quality of production.

This includes tomatoes, cucumbers and summer squash. Make plans to transition these plantings into a heat-loving crop or let the soil rest in a summer fallow period. Rototill some compost, grass clippings and/or leaves into the soil and then cover the surface with a blanket of mulch. The organic materials will break down and stimulate microbial activity. When it is time to plant the fall garden, these beds will be ready to go.

Several types of insects and disease are on the rise in our gardens. Keep an eye out for early signs of trouble. Prompt treatment is important to prevent losses. If you catch a problem early you often have more low-toxicity options for controlling it.

Common problems of late spring to early summer are leaf spots and powdery mildew on melons, squash and pumpkins. This disease is best prevented with sprays rather than trying to control an outbreak after it has done considerable damage.

If your tomatoes are showing twisted, curling foliage in the new growth, the cause may be a virus or damage from a herbicide product. There is no fixing these problems, so go ahead and pull them out and throw away the affected plants. If older foliage is cupping, you can ignore this, as it is a sign of heat and sometimes high-fertility levels. Some varieties are more prone to this than others.

Watch for spider mites on tomatoes, green beans, peppers and some other crops. A strong blast of water upward from beneath the foliage will dislodge many of the pests and create unfavorable conditions for those that remain.

Do this early in the infestation on a weekly basis and you may be able to put off the need to spray. If you wait too long it will be too little, too late and sprays of insecticidal soap or horticultural oil will be needed. These must be applied upward to the bottoms of the leaves where the majority of the mites are hiding and feeding.

Perennials and annuals

The flowers and colorful foliage plants mentioned in May can still be planted in the garden now. Just make sure to provide moist soil so they don’t dry out as they are trying to establish roots after planting. Mulch new plantings with about 2–3 inches of leaves or pine needles to deter weeds and slow evaporation from the soil.

Try some annual vines this summer. They provide fast growth and can be a great way to cover a trellis with colorful flowers. A few of the many choices include morning glory, moonvine, black-eyed Susan vine, cypress vine, hyacinth bean and clitoria.

Some flowers, such as zinnias, leave their spent blooms on the plant and can look unsightly. Deadhead these by cutting out the spent blooms and discarding them. Give all your flowering plants a boost of fertilizer to promote vigor. A lawn fertilizer has a higher first number (nitrogen) and is a good way to increase vigor and reblooming.

Fall-blooming perennials can be sheared back a little now to encourage more bushy growth. Trim back Mexican bush sage, Mexican mint marigold, fall aster and chrysanthemums by about a third. Then lightly fertilize the beds with a lawn-type fertilizer and water it in well to support new growth.

Containers are a great way to add a splash of color to the landscape. Plant some containers of flowering annuals this summer. Choose large containers to minimize the need for frequent watering. Combinations of a tall plant with a medium-sized plant and a trailing plant are especially attractive. Start new containers to replace older ones that are beginning to wane and you’ll be able to maintain a gorgeous planting all summer long.

Continue to watch your flower beds for signs of insects or disease problems. Early detection and treatment are important to avoid more serious infestations.

Trees, shrubs and vines

Deadhead crapemyrtles as the blooms are spent to promote regrowth and more blooms. These are among our most dependable summer flowering plants and some minimal care will help you get the most out of them. Continue to deadhead roses and buddleias as mentioned in May.

Watch for aphids on crapemyrtles as their numbers can quickly build up. They secrete honeydew on which a black sooty mold will then grow. Insecticidal soap and horticultural oil are two methods for controlling aphids but you must contact the insects with the product for best results. Other insecticides are also available for aphid control.

Even though it is summer, you can still plant container-grown woody ornamentals if you are extra careful to ensure their roots stay moist without staying soggywet.

With crapemyrtles in bloom, this is a good time to pick out your favorite colors for adding to your landscape. Make sure the variety is resistant to powdery mildew and that its mature size is appropriate for the planting location. This will help avoid the need for pruning.

Continue to provide young woody ornamental plants a weekly soil soaking to keep them going strong in the heat. Mulch the soil surface to deter weeds and hold in moisture. A 4 to 6-inch mulch of leaves or chipped wood works great and will decompose over time to release nutrients back into the soil.

Scale-susceptible species (such as camellias, hollies, beautyberry and golden euonymus) should be checked periodically for signs of these insects. Sprays of summer oil can be helpful in controlling them, but thorough coverage of all stem and leaf surfaces is necessary for good control.

Fruits and nuts

This month several types of fruit are in their harvest season in most areas of the state. This includes peaches, plums, blueberries and blackberries. Allow these fruit to ripen full on the plants since they will not ripen after harvest.

Keep the soil moist around fruit trees, especially those entering their harvest season. Trees that are carrying fruit for a fall harvest (such as persimmons, citrus and pecans) also need to be kept adequately watered when rainfall is absent. Citrus and persimmons can drop some of their fruit if allowed to become water-stressed.

Maintain a thick layer of mulch around fruit trees. Add more mulch to the surface over the old mulch as it decomposes. This will create a “forest floor” type environment that is very good for tree growth and production. Mulched areas keep weeds and grass from growing up under the trees and therefore keep the mowers and weedeaters away from the tender bark tissues!

Continue to remove watersprouts and suckers from your fruit trees. Even after harvest this practice will keep light coming into the tree’s interior, supporting good growth and eventually good fruit-bud production in late summer and fall.

Pinch out the tips of new blackberry shoots at about 4’ tall. This will encourage branching and better production next year. When you finish harvesting blackberry, prune all canes that produced fruit back to the ground line as they won’t produce again. It is this year’s new shoots that will be carrying next year’s crop.

Lawns and groundcovers

The more often you mow, the more dense and attractive your lawn will be. Keep the blade sharp and it will put less strain on the mower while maintaining a more attractive lawn.

Water once a week or at most twice a week following the practices mentioned in May. Many Texas lawns are overwatered. This just wastes water, costs money and promotes diseases. If you don’t know how long you need to water to apply one half to one inch, use a rain gauge or some straight-sided cans to catch the irrigation and determine the length of time your system will need to be run.

There is no need to fertilize in the summer, especially if you are returning your clippings. People who bag their clippings for the trash pickup are just wasting fertilizer! Recycle those clippings as the perfect natural fertilizer for your lawn. They have the ratio of nutrients grass needs to grow its best.

Areas of the lawn that are not dense are prone to weed invasion. The key to a dense lawn is to mow, water and fertilize properly, but sometimes insect and disease problems can cause it to decline. Early detection and treatment are important, so contact your County Extension Office for help if you are watering adequately and the turf is declining.

Timely tips

Drink plenty of water when working in the garden. Use sunscreen and avoid overexertion as heat stress can sneak up on you. Morning hours are still fairly pleasant and wise gardeners will try to limit their outdoor activities to early morning and late day when the sun is going down.

While watering is critical for keeping our plants strong in the heat, overwatering is deadly. Avoid soggy-wet conditions that drive oxygen out of the plant’s root zone and promote root rots. Whether a plant is in a pot or in the ground, allow it to dry out a bit before you water it again to bring oxygen back into the soil.