Gardening

Alaska gardening Q&A: Lawn mildew, squash plants that won’t fruit, and more

Powdery mildews seem to be the big concern of late. You know you have the problem when you see a light, white coating or a flour-like powder on grass blades, lilac leaves, cottonwood leaves and other plants. It can be quite alarming to see the first time.

Actually, once you see the powders (I say “powders” because there are several types of these mildews), the fungi that create them are already embedded in your plants. That’s right -- they are caused by fungi.

There are a lot of suggestions for getting rid of powdery mildews. These include letting the grass grow longer (always seems to increase the problem in our lawns), getting rid of shade (yeah, right!), increasing air circulation (how?) and, of course, using a fungicide.

Usually, I just live with infestations of mildew in the yard. (In the greenhouse is another story). It spreads by spores and I know, having written a book on fungi (”Teaming with Fungi, The Organic Gardener’s Guide to Mycorrhizae”) that once an infestation takes hold, it is hard to get rid of with anything but an organic fungicide for that particular type of powdery mildew. Since there are so many kinds, available fungicides are pretty broad spectrum; they kill beneficial fungi, too. Use your judgment as to the severity of the problem and your feelings about it.

Next, again, questions from gardeners seeing plenty of cucumber and squash flowers, but no fruits. Be aware that there are two types of flowers involved here, male and female. You can identify the females as they all have a small, “cucumber” structure just beneath the flower. The males do not. If you don’t have insects doing the job, pollinate the females using a Q-tip or small paint brush.

The virus has caused many who wouldn’t otherwise exercise by walking along the road to do just that. As a result, people are seeing wildflowers they can’t remember seeing before or in such profusion. It is because their seeds are being spread by traffic. Hard to believe, isn’t it?

Right now, white sweetclover (Melilotus alba) is displaying white, sweet-smelling flowers, which are going to seed. This plant is a member of the pea family. The first year it grows a foot or so, but the second year, it really takes off and can reach 6 feet in height. It smells good, and you might think it would add vertical texture to your perennial bed, but do not plant this in your yard. See how it spreads on the road? Imagine what it will do in a cultivated bed. You might consider taking a big bag and collecting the stuff along the road in front of your house or place of business.

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OK, sweet peas excel in Alaska, and we grow lots of them here. However, don’t leave them on the vine. It is a good practice to pick flowers (and enjoy them) so they don’t go to seed. You don’t want to see pods forming unless you are going to try and collect seeds. If pods do form, take then off as soon as you see them so the plant will concentrate on making more flowers.

Finally, you remember when Anchorage lost Julie Riley of Cooperative Extension Service fame to the Fairbanks office. Alas, now because of retirement this week, Julie won’t be in her official capacity, helping others selflessly as she has for decades. She is to be highly thanked by all Alaska gardeners and will be sorely missed (in her official capacity, at least!).

Jeff’s Alaska garden calendar for the week

Alaska Botanical Garden: It’s open. There are Thursday picnics and so much more. Go to alaskabg.org.

Lawn mowers: Clean the bottom of yours and it will do a better job mulching up the grass blades. Do not bag. Leave the blades on the lawn to decay and feed the microbes that feed the lawn.

Butter and eggs: Ugh. A terrible weed, no matter how cute you think the yellow and orange snapdragon flowers happen to be. Pull and remove from the gardens, along fences, by sheds and everywhere else you see it.

Clover: Lawns are supposed to have this nitrogen-fixing legume. A pure green lawn is a monstrosity of unnaturalness and a sign that someone loves the lawn more than the family, imho.

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Jeff Lowenfels

Jeff Lowenfels has written a weekly gardening column for the ADN for more than 45 years. His columns won the 2022 gold medal at the Garden Communicators International conference. He is the author of a series of books on organic gardening available at Amazon and elsewhere. He co-hosts the "Teaming With Microbes" podcast.

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