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.

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Fourth of July round-up

Happy Fourth! Here are a few pictures of my perennial and vegetable gardens taken in the last few days.

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The vegetable garden is doing nicely, although the abundant rain has resulted in an abundant crop of weeds. If you look really closely, you can see some small green tomatoes. And check out those big squash blossoms! I picked a small yellow zucchini yesterday and have been picking beans steadily. I pulled out the pea vines this week and am gradually pulling up the lettuce. I will plant more beans in the empty spaces.

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This is part of a mixed border in the front yard. It’s designed to provide maximum color. There’s nothing like the orange of butterfly weed (Asclepias tuberosa). The yellow sundrops (Oenothera fruticosa) and blue harebells (Campanula rotundifolia) are a lovely contrast. The harebells will bloom all summer, and critters don’t eat any of these plants. (The tan stripe in front is the result of a mowing about three days before the picture was taken. The grass had been pretty tall.)

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Bergamot or beebalm (Monarda fistulosa) is at the height of its show, and the display will continue for another couple of weeks.

I hope your life is as colorful as mine on this special day.

6/28/13: In the garden this week

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Late June is always the pink season in my perennial gardens–the place is lousy with bergamot/beebalm (Monarda fistulosa and M. didyma, two closely related native species). Rudbeckia is showing buds, so within a week or so, there will be lots of orange to enliven the scene.

In summer my perennials and woody plants require very little work; my attention is focused on the vegetable garden. Here’s a list of things to attend to this week, in between restful sit-downs in the garden to admire your handiwork:

– keep the grass long (3″ or more) to reduce mowing times. There is no need to fertilize or water. As the weather heats up, the grass wants to go dormant, so let it.

– start to collect perennial seeds: columbine, heuchera, and other spring bloomers are ripening seeds, even as they continue to bloom

— as perennials finish blooming, leave the dead flowers on the plants. The seeds will feed the birds next winter (and you can always collect some seeds later on yourself)

– if you have not already done so, pull out early spring greens, such as arugula, spinach,  and lettuce; pull out pea plants after they finish producing; compost all these plants unless they are diseased

— harvest basil and make pesto to freeze for the winter (see preceding post)

– continue to plant beans, kale, chard, and other members of the brassica clan if you have room; harvest peas, young squash, and beans before they get large and tough. Peas are finishing their brief but delicious run in my garden right now.

– continue to stake tomato plants firmly and remove all suckers

– monitor the vegetable garden carefully for pests and diseases

Happy summer weekend to all!

 

6/21/13: In the garden this week

Beebalm (Monarda fistulosa) began to bloom this week.

Happy summer! Or if, like me, you belong to the minority of people who dislike hot weather, I wish you a cool summer.

My perennials gardens turn pink in late June. Beebalm (Monarda fistulosa, shown above), swamp milkweed (Asclepias incarnata), and queen of the prairie (Filipendula rubra) turn the garden various shades of pink, from cotton candy to subtle mauve. They are enlivened by the brilliant orange of butterflyweed (A. tuberosa) and the subtle whites of wild quinine (Parthenium integrifolium) and Culver’s root (Vernoniscastrum virginicum). And within the next week, the first of the rudbeckias, orange coneflower (R. fulgida) will begin to bloom, and it won’t stop until September.

It’s time to shift from spring to summer mode in the garden. Spring is the time to do–to move, to dig, to plant, to weed–but summer is the time to enjoy the fruits of all that labor. There’s much less to do. It’s time to stop transplanting and start making plans for next year:

– keep the grass long (3″ or more) to reduce mowing times. There is no need to fertilize or water. As the weather heats up, the grass wants to go dormant, so let it.

— start to collect perennial seeds: columbine, heuchera, and other spring bloomers are ripening seeds, even as they continue to bloom

– if you have not already done so, pull out early spring greens, such as arugula, spinach,  and lettuce; pull out pea plants after they finish producing; compost all these plants unless they are diseased

– continue to plant beans, kale, chard, and other members of the brassica clan if you have room; harvest peas, young squash, and beans before they get large and tough

– continue to stake tomato plants firmly and remove all suckers

– monitor the vegetable garden carefully for pests and diseases

Enjoy the first weekend of summer.