Beneficial habitat at home: Weed control and mid-summer update

Red and black lady beetle on zinnia leaf
With all the Japanese beetles I’ve been pulling off my zinnias, it was a pleasant surprise to find a more friendly beetle!

It’s been two months since I since I wrote about the plants I selected to provide habitat for beneficial insects around my home. Today I’ll talk a bit about weed control and how my spring transplants are doing.

Weed control

I have mentioned before that managing weeds turns out to be far more than half the battle when it comes to establishing perennial wildflowers as habitat for beneficial insects. Based on the results from the habitat plots we planted on the edges of our Christmas tree research field, I decided to use mulch for weed management in my home gardens. While mulch does add extra cost, after you make the initial investment of time to spread the mulch, it really cuts down on the time required to manage weeds during the rest of the season. I had a relatively small area to mulch, and was able to purchase some relatively inexpensive mulch made from the brush and leaves picked up by my city. Also, while I haven’t tested the organic matter content of my soil, just digging up some of the grass told me that my soil could use more organic matter. The mulch will eventually help with that as it breaks down. One downside to mulch is that it could block access to the soil for ground-nesting bees. There are some spots of bare ground in other parts of my yard, and perhaps next year I will be a little more deliberate about keeping some areas bare to support these pollinators.

Several freshly-mulched garden beds with small seedlings alongside a house
I decided to use mulch for weed control in my home beneficial insect habitat.

If mulch isn’t for you, you can read more about different weed management strategies we are demonstrating in our habitat plots.

How are things growing?

Like many (but not all) New Yorkers, I have found myself frequently wishing for more rain this summer. According to the closest NEWA station, we only got 1.3 inches of rain in May, 1.44 inches in June, and 1.48 inches in July (so far). This spring and summer is an excellent illustration of why experts recommend transplanting perennials in the fall, and not in the spring. Hot and dry are not ideal conditions for young seedlings just trying to get started. We often get more rain in the fall, and the cooler temperatures mean the transplants are subjected to less stress.

I started my plants from seed, and most of my seedlings were pretty small when I transplanted them the first week of June.

Three seedlings surrounded by mulch just starting to produce their second set of true leaves
This picture was actually taken about 2 weeks after I transplanted my seedlings. They were a little on the small side.

I admit that I also didn’t harden off my seedlings exactly the way you are supposed to. After losing some un-protected plants to marauding bands of squirrels, and lacking a protective structure that would let me keep my seedlings in full sun, I hardened them off on my screen porch. Moving from this environment to the south side of my house in full sun was a bit of a shock, especially when it got so hot and dry so soon after transplanting. I’ve done a lot of watering over the past month and a half, and I still lost more of my perennial seedlings (and some annuals) than I had hoped.

One seedling, surrounded by mulch
There were supposed to be three echinacea plants in this picture. At least one of them survived!

In spite of these obstacles, quite a few of my transplants survived. The blanketflowers (Gaillardia aristata) are the only perennials that look like they will bloom this season. If I had bought seedlings from a local nursery, they might have been bigger and might have established faster. But I can be patient.

Plant with scalloped leaves and a very young flower bud forming at the top
I think I can see the beginnings of a flower bud on this blanketflower.

You already saw the echinacea. Here are some of the other perennials.

Two seedlings with oblong and very hairy leaves on the left (rudbeckia); one seedling with leaves that look like a carrot on the right (pyrethrum daisy). All are growing surrounded by mulch.
Some of the surviving rudbeckia (left) and pyrethrum daisy (right) seedlings.

Not surprisingly, the annuals have grown faster. (Remember, they’re in a race to reproduce and pass on their genes before winter returns!)

Japanese beetles are eating the common zinnias.

Several Japanese beetles crawling over zinnia leaves with many holes
A small consolation is that the Japanese beetles seem to like my roses even more than they like the zinnias. The roses are functioning as a sort of trap crop.

But they are leaving the ‘Persian Carpet’ zinnias alone. It turns out these are a variety of Mexican zinnias (Zinnia haageana), which is a different species than the common zinnias (Zinnia elegans).

Small yellow and red zinnia flower growing on a plant with small, narrow leaves
‘Persian Carpet’ zinnias have smaller flowers, smaller leaves, and no Japanese beetle damage, even though I planted them right next to my roses.

I’ve been picking the Japanese beetles off by hand (knocking or tossing them into a yogurt container of soapy water, then adding them to my compost bin after they drown). I found the beetles to be more sluggish in the evenings (although admittedly I wasn’t out at the break of dawn), and a colleague recently shared this article with me that suggests that hand-picking Japanese beetles in the evening is indeed the best option. This strategy has not prevented all damage (especially on my roses), but I think my plants will survive. And I admit I haven’t picked them every single day.

Looking down into a yogurt container half-filled with water and many dead Japanese beetles
Japanese beetles picked off of my plants and into some soapy water.

The snap dragons have started blooming.

Pink, peach, and white snap dragon flowers in bloom
I planted snap dragons mostly because I like them as cut flowers, although I have seen reports that they support bees.

And so have the calendulas.

Plant with yellow flowers starting to open
Calendula in bloom.

I’ve seen hover flies on the bachelor’s buttons. Remember the adult hover flies are pollinators, while their larvae are voracious aphid predators.

Pink and purple flower with a black and yellow striped fly visiting it
I’ve seen a few hover flies visiting the bachelor’s buttons.

The cosmos and sunflowers (that survived the squirrels and a local rabbit) haven’t started blooming yet, but they’re looking good!

Sunflower and cosmos plants growing well next to the chimney of a house
The squirrels must not have found my first planting of sunflowers, because they and the cosmos planted with them look great!

This spring I ran out of space to start seeds indoors, and since fall is a better time for planting I saved a few perennials for the fall. Last week I seeded butterfly milkweed (Asclepias tuberosa) and some columbine. In the absence of grow lights, and since I’m not an expert transplant producer, I wanted to give these seedlings a good two and a half months to grow before I transplant them.

 

This post was written by Amara Dunn, Biocontrol Specialist with the NYSIPM program. All images are hers, unless otherwise noted.

This work is supported by:

  • Crop Protection and Pest Management -Extension Implementation Program Area grant no. 2017-70006-27142/project accession no. 1014000, from the USDA National Institute of Food and Agriculture.
  • New York State Department of Agriculture and Markets