8/4/17: In the garden this week

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Two Hibiscus plants blooming side by side. Each flower blooms for one day; you can see buds and spent flowers on both plants. Both are varieties of H. moscheutos, rose mallow, a short-lived native perennial that’s incredibly easy to grow. The birds will enjoy the large black seeds in a month or so.

A hot, humid, mostly dry week, despite frequent predictions of rain: my rain gauge registered just under one inch of rain on Thursday morning after Wednesday’s prolonged showers. I watered my new trees last Sunday and will do so again this week unless we get significant rainfall tomorrow.

But this weather is pretty much ideal for tomatoes, which are the most finicky of plants. They love heat, but if it gets too hot they stop forming new fruits. They need moisture, but if they get too much, the fruit cracks as it ripens. And too little of course causes blossom end rot. The trick is to water consistently and deeply.

The summer hiatus is upon us—it’s too late to plant and to early to clean up. But it’s never too early to plan next year’s garden, so take careful notes on what did well and what didn’t, what could go more smoothly, and how things could be changed in future years. I’m thinking of eliminating more lawn in front and perhaps plant a couple of large trees that would eventually turn a sunny border into a shady on.

Here are a few more immediate chores you could do this week:

water new plantings: unless we get a decent amount of rain this weekend (and forecasts do predict rain), go ahead and water newly planted grasses, shrubs, and woody plants. 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. 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 buying seed. Water 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; you should already have cut down the plants once to make pesto.

— be sure 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.

—  It’s too late to plant. Wait 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 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 really 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 around 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.

Most people keep their lawns growing all summer by applying excessive amounts of water. I never water my lawn. Most summers it turns brown–it goes dormant. This summer, with normal rainfall amounts, it’s still green. So here’s another suggestion: stop watering and see what happens. The lawn will not die, and the earth will be grateful.

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Two lawns in my neighborhood at the end of a recent dry summer. The lawn on the left is not routinely watered, but it will green up as soon as the weather cools down or some rain arrives.

— it’s almost time to prune woody plants. You want to prune when the plant is relatively quiescent—when it’s not using a great deal of energy growing, flowering, and fruiting that it has little to spare to healing a wound. This will happen between now and leaf drop 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 shrub that block sidewalks or diseased trees that might fall down.

Enjoy the garden this week!

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The purple glow in this photo is the gazillion tiny flowers of purple lovegrass, Ergostratis spectabilis. This short (12-18″) native grass is impervious to heat and drought, demands poor soil, and displays a cloud of purple flowers and then seeds from August to October. Hard to find, but very easy to grow.