8/18/17: In the garden this week


The perennial border displays its brightest colors in August. Rudbeckia subtomentosa, Agastache foeniculum, and Hibiscus mosceutos vie for attention amid the greenery.

August may be a dull time of year, but not in the garden, when the floral display is at its height. This is the time to sit on the patio with a cold drink and enjoy the fruits of your labor. But while you’re out there, here are a few things you could be doing:

water new plantings: I watered my young trees last Sunday and will do so again this week unless we receive considerably more rain tonight and tomorrow: this morning’s downpour amounted to just over half an inch, and I aim for an inch to an inch and a half per week. Remember that perennials and woody plants that you planted this spring or last fall need supplemental water during dry periods throughout this growing season. The rule of thumb is at least an inch of water per week for newly installed plants. In dry weeks throughout the growing season (weeks with less than an inch of rainfall), you need to water all plants installed this spring or last fall. Trees need supplemental watering even longer: the rule of thumb is one year per inch of trunk diameter. How do you know when we’ve received an inch of rain? You can make a highly sophisticated rain gauge–an old plastic container or tin can placed among the plants. I total the weekly rainfall and decide whether to water my new trees or my clients’ new plantings each week.

— if you intend to plant a second crop of cool-weather vegetables, you should be starting seed. Water the vegetable garden deeply during dry periods, particularly when the weather is hot, and watch carefully for pests and diseases. Removed diseased plants promptly to prevent spread. Continue to remove the flowers from basil plants as they form. And pick those zucchini before they reach the size of baseball bats!

— continue to properly tie, stake, and prune your tomato plants. Most tomato cages are much too small: the plants outgrow them before they start to bear fruit. And unless tomato plants are properly pruned, by pinching out the suckers, they will be so bushy that they’ll be especially susceptible to fungus infections like verticillium wilt. You’ll find general guidelines for growing tomatoes here and specific watering instructions here.

—  do not plant ornamentals like perennials and shrubs until the weather turns cool in fall. During hot weather, plants put their energy into top growth and blooming rather than growing new roots. If you do continue to plant, water very thoroughly and keep an eye on those new plants. They will need extra water during dry periods, as explained above.

it’s also a bad time to fertilize your lawn or to reseed bare patches, no matter what your lawn-care service tells you. Lawn grasses are adapted to much cooler summers than we experience. All they want to do during this time of year is go dormant, so they can’t use any extra nutrients. Here’s a suggestion: don’t feed at all this year. The lawn will look just fine. Or wait until Labor Day and use one application of a slow-release organic fertilizer. Avoid pesticides, fungicides, and herbicides. Pesticides kill butterfly and firefly larvae and native ground-dwelling bees as well as “bad” insects. And garden chemicals are not so great for kids or pets either; common herbicides, in addition to killing butterfly host plants like violets, are carcinogens. Best to avoid them.

— this is a good time to prune woody plants. You want to prune when the plant is relatively quiescent—when it’s not using so much energy growing, flowering, and fruiting that it has little to spare to heal a wound. This quiescent period occurs between now and leaf drop (abscission) in fall. Basically, when you see that the plant has finished fruiting and that it has formed next year’s buds, but the leaf color is not fading yet, you have a window of time for pruning. Of course, you should prune diseased or injured plants at any time as well as remove any safety hazards, such as overeager shrubs that block sidewalks or diseased trees that might fall down.

do not deadhead your perennials. Seeds represent winter food for birds and other creatures and new plants for you. Collect seeds as they ripen, and store them in a cold place (such as an unheated garage) for next year’s planting, or simply scatter them on the ground where you want them to grow. Do deadhead potentially invasive plants like butterfly bush, miscanthus, and pennisetum grasses however.

Enjoy the garden this week!

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Nodding pink onion (Allium cernuum) is not flashy, but it’s nonetheless a star of the August garden. This is a front-of-the-border plant that thrives on full sun and dry soil.


Rudbeckia triloba has just started blooming. I’m always very happy to see it. The flowers are just so cute.


Tips for growing tomatoes: Tieing and staking


How the garden has grown in the past week! Compare this photo, taken today, with one taken less than a week ago–notice how much taller the tomato plant in the center is.

Right now, while tomato plants are growing rapidly, is the time to take steps that will safeguard the harvest you’re so eagerly looking forward to. Many factors go into a good tomato harvest–the weather, certainly; spacing the plants at least 24″ apart (36″ is better), watering deeply and in the morning so the leaves dry off–but two things that are very, very important are proper staking and removing suckers.

Lots of people buy those little 3′ high tomato cages and are surprised when the plants outgrow them. Tomato plants are generally more than 5′ high, so a 3′ cage will be pretty useless come September–the plant will grow out of it and the whole thing may even fall over. Instead, buy or make stakes that are 7-8′ high, sink them in the ground at least a foot (preferably when you put the plants in to avoid damaging the roots), and continue to tie the main stem to the stake as it grows, using some kind of twine or old pantyhose.

Use a figure-8 tie to attach the plant to the stake, as the photos show:



Put the tie around the stake, cross the two ends, and then put them around the plant. Finally, tie a knot. Leave lots of room–the stem grows fatter as the plant grows taller.

It’s also important to remove suckers, extra branches that grow between the main stem and the leaves:


Pinch them off with your fingernails or use clippers to remove them. This will result in better fruit and healthier plants, because the plants will not become overgrown and crowded, making is easier for fungal diseases to spread. It will also make it easier for you to see and harvest the fruit when the plants start producing. Attending to these two chores–tieing and pinching–each week will give you a better harvest.

There’s lots of good information about growing tomatoes on the web and in books. Sites belonging to university extensions are particularly reliable and will not be in business to sell you things you don’t need. Two good sites are those managed by Rutgers and by the University of Missouri extension.

Check back soon for a post on watering and fertilizing tomato plants.