8/18/17: In the garden this week

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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.

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

8/11/17: In the garden this week

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Some clients resist planting native grasses; resistance usually ends when they see the colors of little bluestem (Schizachyrium scoparium). Look carefully at the blues and purples in this plant, and remember that every plant is slightly different.

We are into what I think of as the summer doldrums, or maybe just a reli=atively q uiet period in the garden. Certainly the prairie perennials continue to bloom with all their might, and there are all the asters to look forward to, but in the ornamental garden there’s not much to do except to keep things tidy (that is, if you like your garden to be tidy).

Still, there’s always something to do in the garden, and here are some suggestions:

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. We received just under an inch of rain so far this 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. 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 and 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; 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.

— it’s 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.

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A branch of a large native hazelnut shrub (Corylus americana). It has finished setting fruit as well as forming next spring’s flower buds–the tiny things hanging down from the leaf nodes will become the male flowers. The plant is resting before its last remaining task of the year, leaf abscission, so this is a good time to prune.

do not deadhead your perennials. It will soon be time to collect seeds, which represent winter food for birds and other creatures and new plants for you. Store your seeds in a cold place (such as an unheated garage) for next year’s planting or simply scattered on the ground where you want them to grow. Do deadhead potentially  invasive plants like butterfly bush, however.

Enjoy the garden this week!

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Rudbeckia triloba is in bloom now and will put on a display through September and into October. This is a short-lived perennial that readily self-seeds, so new plant appear each year. It remains a manageable 3 feet tall and doesn’t spread aggressively. And the flowers are adorable!

 

 

Wild fruits

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Look closely under the leaves: those aren’t strawberries. They’re fruits of trillium, probably nodding trillium, T. cernuum.

We hike a short stretch of the Appalachian Trail at exactly the same time each year as part of a citizen-science project. It’s a shady upland (in other words, relatively dry) section with great variety of habitats: some areas are primarily sugar maple, some are mostly ash; there are areas where less common trees, such as hackberry and hophornbeam, predominate. The understory is extremely varied and primarily native. In the past few years it’s been quite sparse because of drought. This year, with normal rainfall, it  was lush and incredibly varied. I saw fruits I’ve never or only very rarely seen before, such as this trillium. Here’s a detail of that fascinating looking fruit.

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Notice that the fruits of many native shade plants hang down beneath the plant. Why do you suppose this is? What creatures will eat these fruits?

And here are a few more unusual fruits from the same area. For an interesting exercise, look these plants up online and see how lovely their flowers are in spring. And think how great they would look in your garden if you have an area with deep shade where “nothing will grow.”

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Mayapple, Podophyllum peltatum. The fruit is ripe; the leaves have just about gone dormant. This is a great garden plant for deep shade, and it’s commercially available. It gradually forms a large colony.

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Doll’s eyes, or white baneberry, Actea pachypoda. Also easily available commercially.

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Blue cohosh, Caulophyllum thalictroides. Notice the Christmas fern ((Polystichum acrostichoides) on the right.

Take a look at this post for more native plants that grow well in deep shade.

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.

 

In the garden today

Here are some new pictures you might enjoy:

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Berries of cranberrybush viburnum, V. trilobum, look almost too beautiful to be real. Soon they’ll be bright red, but despite that attractive color, birds don’t eat them until winter.

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A detail of the flower of nodding pink onion, Allium cernuum.

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And a view of several flower heads. This is a great front-of-the-border plant, only about 18″ tall.

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As orange butterfly weed (Asclepias tuberosa) finishes blooming, the Rudbeckias take over for the rest of the summer. This is R. subtomentosa, an indomitable plant if there ever was one.

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Wild petunia, Ruellia humilis, is another great front-of-the-border plant. It’s perennial and well-adapted to poor, dry soil.

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And let’s not forget about shade plants for summer color. Great blue lobelia, Lobelia siphilitica, blooms throughout the month of August and into September.

7/28/17: In the garden this week

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This plant combinations says “the height of summer” in no uncertain terms. The Rudbeckia will be in bloom until September, but the Vernonia (ironweed) will only last a few weeks.

Who says there are only four seasons? To me, we are transitioning from early summer to what I think of as the height of summer: the brightest-colored flowers are blooming, native fruits are ripening fast, fall bloomers such as asters are showing buds, and some late-summer plants, such as great blue lobelia, are coming into bloom. And of course, tomatoes are beginning to ripen fast in the vegetable garden. Here are some not-too-strenuous garden chores for this hot weather (in addition to weeding, made necessary by a season of normal rainfall, in contrast to the past couple of years of drought.

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.

— all vegetables, including tender crops like tomatoes and peppers and corn, should be planted out by now, and it’s time to remove early greens like lettuce and spinach. In fact, 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 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 col in fall. Once the weather turns hot, 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 too late to fertilize your lawn or to reseed bare patches, no matter what your lawn-care service tells you. 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.

— 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 first blossoms of Hibiscus moscheutos, rose mallow, opened this week in my garden. This native hibiscus is a short-lived perennial that self seeds readily, produces flowers of different colors, and is very easy to grow.

Powdery mildew

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Powdery mildew, a harmless fungus infection, on leaves of beebalm (Monarda fistulosa). Notice that the plants bloomed heavily despite the infection and that neighboring plants of unrelated species are unaffected. Beebalm almost always gets powdery mildew.

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Powdery mildew on coralberry (Symphoricarpos orbiculatus). Again, despite the infection, this vigorous shrub is quite healthy and about to bloom on schedule. Coralberry rarely gets powdery mildew, but we’re having a rather wet growing season.

Powdery mildew, like most of the diseases that infect plants, is caused by a fungus, or rather a large group of related fungi in the order Erysiphales. It unsightly but completely harmless.

What should you do about powdery mildew? Absolutely nothing. It is a cosmetic problem and will not harm your plants. To prevent it or reduce the incidence, you can use some commonsense horticultural practices, such as preventing overcrowding or watering in the morning only. If you feel you must treat it, a mild spray of milk, diluted 1:10 with water, has been shown to be effective. But remember that almost everything you do in the garden may have unintended consequences, such as changing the pH of the soil or killing butterfly eggs.