June was one of the wettest starts to summer in Arkansas that I can remember. For many that meant horrid flooding. There was a bright side for those who were spared, and that was lower water bills. Mild temperatures also prevailed until the end of the month. In gardens that were not drowned, the plants are growing as never before. Gardeners everywhere are commenting on the amazing number of blooms on gardenias and hydrangeas, plus more fruit than we often see.
• It is time to dig potatoes. Garlic and onions are also being harvested. Some gardeners are doing their final harvest of broccoli and cabbage, side-by-side with tomatoes and squash.
• As you free up garden space, replant with something else. Heat-loving vegetables include okra, southern peas, sweet potatoes and tomatillos.
• There is also still time to plant pumpkins, winter squash and gourds. They take up quite a bit of real estate, so give them room to grow, knowing they will be there through fall.
• Insects and diseases are also making their presence known, and weeds are happier than ever before. You can't ignore a garden for long or something unpleasant takes over. Pay attention to how much rain your garden gets. Water as needed.
• Tropical plants are thriving with the humid and warm weather. To keep them blooming at their peak, don't forget to fertilize and water. Container-grown plants are even more in need of care than those planted in the ground. A finite amount of soil is going to dry out much more quickly. Regular watering leaches out fertilizer, so don't forget to feed potted plants. Whether they're in the ground or in a pot, make sure they are well watered before using liquid fertilizers; and water-in the powdered ones. Frequent, light applications are much better than heavy amounts.
• If your garden needs a boost of color, nurseries and garden centers still have a good supply of tropicals. Don't think it is too late in the season -- they will typically bloom up until a hard frost.
• Perennial plants are also doing well. Summer bloomers, such as coneflowers, black-eyed Susans (rudbeckia), blanket flower and coreopsis, will bloom more freely if you dead-head. Cutting off the spent flowers prevents them from setting seeds and directs energy back into more flower production.
• Bearded iris plants finished blooming months ago, and later in July is the perfect time to dig and divide them. They should be divided every three to five years. Division takes place in mid-July to mid-August since the plants are usually dormant then. You can thin the clump, leaving parts still in the ground, but what is more commonly done is that you dig up the clump of rhizomes and separate them. When dividing them, you typically want to cut the fan of leaves back to about 6 to 8 inches. Cutting the foliage is helpful for sanitation, but it also prevents the wind from uprooting the shallowly planted irises until their roots re-establish.
• Most gardenias are finishing up their big show, with a few still having fragrant flowers. If you have gardenias that need pruning, do it as soon as the flowers finish. Many of the newer varieties will rebloom off and on throughout the summer, but their biggest display is set in the fall as they are going dormant, and those flowers are finishing now. Prune with selective cuts to thin the plant to reduce height. Avoid the sheared, meatball look. By pruning soon, you will give them time to recover and bounce back to set flowers for next year.
• Big leaf hydrangeas and oakleaf hydrangeas are like gardenias in that they bloom in the summer and set flower buds for next season at the end of the growing year. Oakleaf hydrangeas are nearly finished with their blooms, while the big leaf hydrangeas are still coming on strong with pink and blue flowers. When the flowers of both types begin to fade -- oakleaf blooms fade to pinkish-tan, and big leaf hydrangeas to a more mottled version of their peak bloom color -- will be the time to prune, if needed. Unlike gardenias, hydrangeas have multiple canes and so rather than thinning the branches, remove the older, thicker canes at the soil line. This will still leave you branches or canes with flowers on them and reduce the plant's overall size. The panicle and Annabelle type hydrangeas, which are mainly white, are just starting to bloom and should be left alone. They bloom on the new growth. Any pruning that is needed for them should be done in late winter before new growth begins.
Term of the month: pH
Horticulturists often recommend having your soil tested to determine the pH of the soil. Soil pH (potential hydrogen) is very important because it affects the availability of nutrients to plants and the microbial activity in the soil.
Some plants need an acidic soil to grow well, while others prefer a neutral soil or alkaline soil. If the pH -- acidity or alkalinity -- is not in the range the plant needs, the nutrients that may be in the soil will not be available for the plant to use.
Soil pH is measured on a scale from 0-14. Since 7 is right in the middle, that is considered a neutral pH. Anything below 7 is acid, while above 7 is alkaline.
In general, the majority of plants do best with a slightly acidic soil between 6 to 6.5. Acid loving plants, such as azaleas, blueberries and potatoes prefer a pH around 5 to 5.5.
You may think that one point won't make a difference, but it does. The pH scale is logarithmic, so a change of one pH unit reflects a tenfold change in acidity or alkalinity.
If the pH of the soil is too high for azaleas, the leaves will turn yellow and the veins will be green. It is because the plant can't absorb the nutrients in the soil, particularly iron, and the plant begins to decline.
Potatoes can develop a scabby skin if the pH is too high, so never lime where you are planting potatoes.
Big leaf hydrangeas are pink in alkaline soil, purple in neutral and blue in acidic.
In Arkansas, our native soil pH is acidic, but it can vary from county to county. It can also change by what you add to your soil in the form of fertilizer, amendments and activity. The addition of new concrete sidewalks or patios can raise the pH of nearby soil.
Knowing your soil pH is important. You can take a pint of soil to your local county extension office for a free soil test. It will usually take a few weeks to get a computer report back. Once you know your pH and the needs of your plants, you can raise an acidic soil with the use of lime, and lower the soil pH with sulfur or aluminum sulfate. Your soil test will provide guidance.
Read Janet Carson's blog at arkansasonline.com/planitjanet.
Azaleas need an acid soil or they can’t absorb enough iron to thrive.
Potatoes are acid-loving plants that become scabby in alkaline soil.
HomeStyle on 06/29/2019
Print Headline: Breaking ground