Don’t plant mayday trees. Don’t even let your existing ones remain.

There are too many things to write about this week, and not enough space to string them together, so let me abruptly jump around a bit.

First, we just finished "invasive weed week" in Alaska and this is as good a time as any to scold, berate and excoriate those of you who are still of the mind that it is OK to plant or even maintain mayday trees … officially known as Prunus padus and, informally, European bird cherry. What? Stop immediately!

This is an invasive tree. Period. It is a bully. Yes, it can be called beautiful, but so what? Stop planting them. They take over riparian areas. They produce chemicals that can kill moose. They push out native plants.

Introducing this tree to Alaska was a terrible mistake made by pioneers. Now we know better. This plant is high on the list of no-nos for Alaska gardeners. Again, it doesn't matter that they might be pretty. Stop planting them and get rid of what you have. Pull any trees that are 2 inches in diameter. Bigger trees should have trunks and all roots removed. Keep at those seedlings and runner plants that pop up in your lawn. By the way, if you are a master gardener advocating for this tree, you should be stripped of your credentials and banned from the yard. Harsh words, but this is such a bully of plant.

Moving on, the "half-off" sales have started at the local nurseries. This is a sure sign that they will soon be out of annuals and vegetables to fill in holes in your plantings. If you need stuff, better go and try and find it right now. Do not delay. Go today, if possible. You may already be too late. Look for other stuff on sale, however, such as trees and shrubs.

On the weed front, the first dandelion flush has receded. Now all you really need to do is keep the occasional flowers from going to seed. Mow them before they open or pick by hand. Of course, you should continue to do a bit of pulling with hand tools. If you are worried about the seeds that blew in, an application of corn gluten (not cheap) will prevent them from germinating. The effect lasts six weeks. It won't kill existing plants. For that you need an organic herbicide — but don't expect any of them to be 100 percent effective.

OK, how about a bit of weed eating? Sure, you can eat chickweed and dandelions, but here I am talking about getting out the weed whacker and going to work. Plants grow a tremendous amount during an Alaska June and now is the time to neaten things up. These tools are great for cutting down equisetum, grasses and weeds along buildings, swings, fences, under shrubs and around trees. Be courteous of your neighbors as these can be loud and irritating machines. Make sure to put on safety glasses.


Loud and irritating also goes for the leaf blower. After you weed whack, consider getting yours out and cleaning things up — not only the trimmings, but your driveway, porch and walks. A rake will do, too, but not as well. Remember how clean things look after the street cleaner goes by? Wear ear protectors.

Next, if you are like me, you are seeing plenty of yellow jackets and wasps, but darn few bees. Make sure your tomatoes, peppers and squashes are being pollinated. You can use a fine paint brush and be a bee. Shake tomato plants gently for a minute or so. Make sure flying insects can get in and out of your greenhouse.

As for those wasps and yellow jackets, they are really beneficial and eat lots and lots of aphids, among other things. Of course, nests attached to the house or in a tree that impact humans have to go, but leave the rest alone.

It should be obvious — but obviously isn't — that tall plants need staking. And, it is not just the tall plants; plants that produce heavy flowers, particularly peonies, need staking. You can figure out which need help. A recent trend is to use branches, as they make the garden look more natural, but anything will do from tomato stakes to dowels. Just do it before we get some really heavy rains or wind.

Finally, in an organic growing system, microbes feed plants. Now is a great time to add more microbes to your soil so that they, in turn, can fertilize your plants. The two best ways to do this are to add compost or use a compost tea, both of which you can make or buy. A third way is to feed existing microbes so they will breed and multiply. Consider an application of a soluble, liquid organic fertilizer (actually microbe food as you are feeding them, not the plants) or a side dressing of soybean meal.

Jeff’s Alaska garden calendar

Thin: Thinning is not a one-time thing. You have to keep at it. Are your beets, for example, far enough apart?

Greenhouses: Make sure yours have enough ventilation. Temperatures above 90 degrees are too hot for most plants.

Peony time: If you haven't seen the peonies at the Alaska Botanical Garden, do so. And, check out the new greenhouse, the fabulous Heritage Garden. This is where you need to send Uncle Bob and Aunt Martha when they visit!

Over-the-fence plants: This is the term used for plants neighbors give you. Be very careful. Look to see where they came from and consider if the gift will become invasive.

Jeff Lowenfels | Alaska gardening and growing

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’s authored several books on organic gardening, and his latest book, "Teaming With Bacteria," is available on Amazon. Reach him at