Fall is upon us and gardening is starting to wind down, but it isn’t over yet and you may have some questions. For answers, turn to Ask an Expert, an online question-and-answer tool from Oregon State University’s Extension Service. OSU Extension faculty and Master Gardeners reply to queries within two business days, usually less. To ask a question, simply go to the OSU Extension website and type in a question and the county where you live. Here are some questions asked by other gardeners. What’s yours?
Blackberries were mulched on this hillside. What's a good option for erosion control?OSU Extension Service
Q: I had blackberries mulched on our hillside. The dirt is sandy. What ground cover would you recommend to stabilize it? – Linn County
A: I’m going to send you links to a lot of information. I’m attaching an article that discusses two native grasses that are good for erosion control. Both are types of wild rye (‘Arlington’ and ‘Elkton’). You could plant the grass now and then change over to something else next year.
Other good options for ground cover would be coastal strawberry (Fragaria chilioensis) and kinnikinnick (Arctostaphylos uva-ursi).
Here is a link with pictures of more ground covers you could use.
And if you would like to use shrubs instead, here is a list of trees and shrubs for erosion control. – Deborah Kern, OSU Extension Master Gardener
Does deer resistant equal deer danger?OSU Extension Service
Q: I bought a pound of a wildflower seed mix that is said to be deer resistant. We like having deer in our midst and don’t want to plant something that might be harmful to them. I haven’t searched all the seeds on the list yet, but the mix does include foxglove, which I read is poisonous to humans and animals, including deer. Should I not plant them or do deer know not to eat them? – Lane County
A: Foxgloves are not native to Oregon, but they have been introduced and do grow in many areas. This does not seem to cause problems for deer. So, I wouldn’t be worried. Since most of the species in this mix are not native, it would be advisable to plant the seed in your garden, but not in wildland areas. This will benefit deer and all the species that depend on native plants. – Chris Adlam, OSU Extension regional fire specialist
Epimedium in a garden.OSU Extension Service
Q: I have a shady garden and have several epimediums. They seem to be attacked by a pest that is eating the leaves. Do you have any ideas what this might be and how I can treat my plants before it is too late, or before it spreads to other plants? – Multnomah County
A: The good news is the brown edges reveal the damage is old. Thus, the pest is already gone. I see only a few lesions where the edges of the missing tissue is still green. In those few cases, you would be wise to look at the undersides of the leaves, then either squash or brush the critters you find into a glass of slightly soapy water, where they will drown. Another bit of good news: The total damage is less than 10% of leaf tissue. Thus, the small amount of damage won’t affect the health of the epimediums, nor will it affect year-to-year performance. Then, too, the leaves will soon drop of their own accord. Keep an eye out when the fresh new leaves appear, as the choice succulent tissues are favored foods of insect pests. – Jean Natter, OSU Extension Master Gardener Diagnostician
Q: I want to install a desert-like landscape for a north-facing yard with extreme sun and heat. Can I plant a seguro cactus in Willamette Valley or are any other cactus OK? – Lane County
A: You are fighting our climate to try to establish a desert landscape in this valley. No desert endemic cactus will survive our water-logged soils here in fall through spring. Many sedums will do well. You will need a well-drained soil for most succulents, also.
See the info in this link for suiting the plant to a hotter, drier area while still keeping it alive over the winter. – Pat Patterson, retired OSU Extension horticulturist
What's ailing this lilac tree?OSU Extension Service
Q: This lilac tree has been growing in this partially shaded southwest location since 1985. It’s watered regularly, but not deeply. It has been doing fine until this past summer. Is it dying? How can I save it? – Yamhill County
A: You get to be the plant detective for your lilac. Ask yourself, has anything changed around the lilac this year? Have trees been removed or added? Has the soil in the area been disturbed? Has the drainage around the lilac changed? Now, dig some small holes around your plant to see if the soil is dry about 6 inches below the surface. If it is dry, then the shrub simply needs more water. It could be that because of the stress of the long, hot and dry summer the shrub has developed a fungal disease called verticillium wilt. Here’s a link to an Iowa State University Extension publication on verticillium wilt, which will give you more information. The next publication from Michigan State University Extension provides even more information. You need to examine some of the branches for vascular streaking. This publication tells you how to do that task. The results of your examination will determine your next steps regarding the lilac. – Anna Ashby, OSU Extension Master Gardener
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