Ask an Expert: The “Weed-Free” Native Plant Plan Is a Big Ask

Gardening season is in full swing and you may have some questions. For answers, check out Ask an Expert, an online question-and-answer tool from Oregon State University’s Extension Service. OSU Extension Teachers and Master Gardeners respond to questions within two business days, usually less. To ask a question, simply go to OSU Extension Website, type it and the county where you live. Here are some questions asked by other gardeners. What is your?

Q: In anticipation of fixing our septic system and having our yard dug up, we would like to replace what we have now (grass and especially weeds). We live on 0.9 acres and have planted native shrubs, trees and plants.

We have a butterfly garden. We are looking for ideas. Primarily, we want it to benefit birds, bees and other insects. The plants shouldn’t need water in the summer or a lot of weeding. We want to be able to walk there. – Benton County

A: My first thought is more native trees, shrubs and plants. Consult a nursery specialist who specializes in native plants. If the cost is prohibitive, perhaps pay for the concept drawing and then do as much of the work as possible yourself or have smaller portions done over time.

Maybe add some taller native trees that will become shade trees to diversify the different types of habitats available. Native plants are best adapted to our climate and birds, bees and insects have evolved with them. There are very few plants that can go without summer water during our summer, especially while they are getting established (think last year’s summer).

For me, keeping a “walkable” weed-free place means establishing some type of path system for you to move around the plantations. Paths can be gravel or natural materials such as hazelnut shells, but keeping weeds free can be difficult.

Perhaps planting larger expanses and creating larger areas of flowering plants that bloom at different times of the year would create interest over a longer period of time and lots of different habitat and foods for different insects and birds.

Birds like many levels of plant height, from trees and tall shrubs to small shrubs and ground covers, because many different habitats are created for different birds with different nests and foods and escape needs. predators. Another surefire way to attract birds is some sort of water feature, preferably with moving or cascading water and shallow areas to encourage birds to bathe and water. Moving water also discourages mosquitoes.

The absence of weeds is the biggest demand here. Without adding some sort of ground cover to compete with the weeds, you’re bound to have some. One suggestion would be to learn to live with a few weeds. Weeds can also provide birds and insects with food and habitat.

Finally, I live in a neighborhood as your photo shows. I don’t think you would want to plant on your septic field. Be sure to speak with your contractor before planting anything in this area. There is a long list of sources listed on pages 5-7 of the following document to provide more information to help you make the best decisions for your property. Gardening with native Oregon plants west of the Cascades. – Debra Lauer, OSU Expansion Master Gardener

Q: The previous owner planted a trumpet vine that took possession of our property and the property of adjacent neighbors. We cut it last year, but it came back with a vengeance. And, it also sends shoots everywhere. I have tried drilling holes and putting Epsom salts in the holes, to no avail. I am at my wit’s end. – County of Marion

A: There are two effective options. The first is to dig up as many roots as possible, then continue to remove any bits of the plant as soon as it reappears. Eventually, the root will starve and die from lack of photosynthesis.

The alternative is to use a systemic herbicide like glyphosate (example: Roundup). The best approach is to cut the vine back to about 1 foot tall, then wait for vigorous new growth. At this point, you can spray the plant (making sure to protect all other plants and surfaces, following label instructions).

Another method is to cut the foliage about 1 foot high, then immediately apply the herbicide to the cut stems, again being very careful not to get any on desirable plants. Plan to complete your control activities at least six weeks before fall leaves begin to fall so that the herbicide is transported through the plant’s vascular system to the roots. Once the plant begins to slow down for the winter, the herbicide is much less likely to be effective.

I should add that Epsom salts are not effective as a herbicide or for most other garden uses despite what you read on the internet (i.e.. blossom end rot on tomatoes.) Epsom salts contain only magnesium. Unless your soil is deficient in this nutrient (which is very rare), you end up applying a mineral that just washes and degrades rivers and streams. – Lynne Marie Sullivan, OSU Expansion Master Gardener

Q: What is your advice on planting milkweed in Lane County? Yesterday I bought three ‘Red Butterfly’ Asclepias curassavica plants, which the honey bees seemed to like very much. I haven’t planted them yet. After reading more about them and the possible negative effect on the monarch butterfly, I’m wondering if I should return them. – Lane County

A: You are correct to note that the planting of this species (called Mexican milkweed) has sparked debate among entomologists, as described in this article.

The native species found in the Willamette Valley is Asclepsia speciosa or showy milkweed. Since the science on non-native (Pacific Northwest) species is unsettled, you may be able to save your purchases and plant showy milkweed to increase the varieties available in your garden. – Kris La Mar, OSU Expansion Master Gardener

PillsOSU Extension Service

Q: You’ve probably received a lot of questions about woodlice this year. For the first year they devastated some of my vegetable beds. And these are not just seedlings, but also well-established plants.

I tried many well-known solutions, from traps to barriers. I tried to minimize water and provide plenty of water. I even tried to remove them. But they come back in large numbers and eat the stems of plants like zucchini and bush beans. My neighbor has the same problem, so I don’t think it was something I did on the floor in particular.

So I have two questions:

  • Are there any steps I can take to prepare for next year to try and reduce their numbers?
  • Have people had success using black plastic mulch?

Although the focus has been on the stems, something is also eating the beans themselves if they touch the ground. I saw beans with holes with a woodlouse sitting on the hole. My neighbor said she had woodlice all over a half-eaten zucchini. Luckily, although my zucchini stalks were affected, the fruit itself was not.

It started in early spring with my broke boots. And it continues today. Pretty much every bush bean plant I have in a bed has been affected. Only one seems to have escaped.

Here’s another hint: damage seems worse in warmer, drier weather. Is it possible that with the wet spring I grew a bumper crop of woodlice and once the weather turned hot and dry they were thirsty, seeking moisture from the plants?

All thoughts are welcome. I’d love it if the woodlice weren’t the problem and there was something else I could eliminate. – Multnomah County

A: We actually get few questions about pill (and sow) bugs because they feed on decaying organic matter, not living plants like this publication noted.

Damage is caused by either borer or caterpillar. They both lay eggs in the ground, which hatch and mature by eating whatever is nearest; roots and stems. As their work is done at night, you won’t see them, just the damage they cause. Organic matter decomposes (rots) faster at high temperatures and therefore becomes food for the woodlice you see.

here and here are descriptions of the most common pests that fall into the categories borers/caterpillars. They are opportunistic pests. If fruit touches the ground, they will feast on it. Many gardeners hang zucchini and pumpkins in netting or nylon tubing (if someone wears them more). You’re going to have to research at night, so see what emerges at night. – Kris LaMar, OSU Expansion Master Gardener

Christy J. Olson