Gardeners from Oregon turn to the experts at Oregon State University Extension Service and Master Gardeners for answers to their questions on topics ranging from growing tomatoes and replacing their lawn to weeds and composting. In 2022, the following questions were the top 10 most read gardening questions Kym Pokorny shared with The Oregonian/OregonLive readers. Follow the links in each question to find the full answers.
For answers to your questions, contact Ask an Expert, an online question-and-answer tool provided by Oregon State University’s Extension Service. OSU Extension faculty and master gardeners respond to inquiries within two business days, usually less. To ask a question, just go to the OSU Extension website, type it in, and include the county you live in.
Q: I am currently mulching the final portion of my traditional lawn and plan to trim and seed it in the spring. I was thinking about micro clover or envirolawn. Can you tell me the pros and cons of each and what works best in my area? Room is level, 18′x18′ with sun to partial sun exposure. – Multnomah County
A: According to Oregon State University professor emeritus Tom Cook, the person who developed ecoturf, “Clover by itself is not persistent enough to provide a viable turf for more than a few years without regular reseeding. It’s more drought tolerant than grass, but it still needs watering.” Also, clover should be mowed to look its best as a turf and to withstand normal wear and tear, explains Brian McDonald, turf expert at OSU Extension.
Q: I’m looking for information or a book recommendation on composting, specifically how to compost weeds to kill the seeds. – Lane County
A: I have been composting for over 40 years and teaching composting for 30 years. In my experience, people who really want to compost find a method that suits their physical ability and lifestyle. … As for composting weeds, my rule is never to put anything in the compost (weed seeds, diseased plant tissue) that I don’t want anymore, writes OSU Extension Instructor Linda Brewer.
Q: I have a compost bin (about 40 gallons) that I’ve been filling with kitchen waste (just uncooked vegetable and fruit scraps, tea leaves, and coffee grounds), yard waste, and shredded paper for about six months. It’s about half full. I rotated the mug when adding new material. A lot of small flies (like fruit flies) have been swarming around the compost for the past month or two so I wear a mask when opening it to avoid them flying in my face. … What can I try to reduce the flies? I’m trying to get my family on board with home composting but the flies disgust them! – Jackson County
A: I can assure you that you won’t go wrong. If your mug is anything like mine, it has shielded vents somewhere and these little flies get in there. OSU Extension senior faculty research assistant Linda Brewer suggests some tips to reduce the number of flies.
A huge walnut tree grows in a wild backyard across from the high fence of my property. Its canopy extends into our garden and creates dense shade. I was unlucky to get my newly planted plants (mostly native) to thrive there.
Do you think the walnut tree is to blame for this problem? If yes, what would be a solution to fix this problem? — District of Clackamas
A: The walnut species has a chemical that slows (delays) the germination of seeds and causes growth problems in many other plant species. The chemical is juglone. I can’t tell you from the information you have provided if this is the problem with your own installations or if something else is going on. What I can do is give you a list of plants that are tolerant and sensitive to the juglone (many of which are native) so you can use plants with a greater likelihood of success, writes Kris LaMar, OSU Extension Master Gardener.
Q: I can find lots of information on what kills Crossbow, but no specific information on how it does it. I’m trying to kill wild blackberries. My garden is in a gated community and is right next to my neighbor who doesn’t like herbicides. She tells me if I spray the blackberries that are next to her organic fruit tree, the herbicide will transfer to all the roots in neighboring plants, killing them. As far as I can see, Crossbow behaves in the same way as Roundup, migrating from the leaves to the roots, only killing or damaging those that have sprayed leaves. Can you give me information on how it kills plants and if the herbicide is root transferable to other plants? – Circle of Clackamas
A: First I should tell you that the crossbow is not marked for use in courtyards. You should take a different approach/product in this setting, but I want to go further to answer your question.
Learn more here. Let’s just say Kaci Buhl, OSU Extension pesticide specialist, is glad this gardener reached out before making a decision.
Q: Some of the owners in our condominium complex are clearing ivy from the natural areas on the property. We piled it up and let it dry before loading it into the dumpster, a large 40 cubic meter container that is picked up by the county. We wonder if this process is necessary. We were concerned that the removed ivy would be spread as mulch and spread elsewhere. Or would it be better if we just tossed it straight into the dumpster. —Washington County
A: Regarding the disposal of ivy plant material after removal, at least one OSU source warns, “…since ivy will regrow from tiny fragments, please do not mulch or attempt to compost the ivy you remove, just bag it up and throw it in the trash.”
Learn more about preventing the spread of ivy from Kris LaMar, OSU Extension Master Gardener
Q: The trees on my property have long branches that mature in spring and summer. Do I have to cut them back? I’m afraid that cutting will only create more, so I always have to cut them back. The trees are 20 years old. They are watered with a sprinkler three days a week. No fertilizer. I think they are maples. — County Yamhill
A: Oh my god. It looks like an arborist has repeatedly visited your neighborhood to “prune” the trees, not just your trees, but your neighbors’ too. The method used is a variation of the topping, sometimes referred to as “round over”. Unfortunately, this type of pruning is rarely, if ever, recommended by properly trained arborists. (See “Top No Trees!”)
Find out what OSU Extension Master Gardener Diagnostician Jean Natter recommends to help this tree.
Spring brings buds and blossoms, but also moles, voles and ground squirrels. The small mammals bring gardeners to their knees to peer into tunnels, set traps, and throw in everything from kitty litter to chewing gum. They wage war against the critters before they know what they’re fighting, which can lead to frustration. “How you deal with them depends on what you have,” said Dana Sanchez, wildlife specialist for Oregon State University’s advisory service. “The traps are different and so are the baits you would use.”
Learn more about the assessment and control of the critters here.
Q: Every time I look at my front yard, I see more and more clover. I don’t want to use anything on the lawn that isn’t organic. It sounds like clover is a sign of low nitrogen levels. I found some information about Klee here and on other sites and it confused me even more. Should I add fertilizer (and if so, which one)? Or shall I uproot the clover and put grass seed in its place? Or just ignore the clover and accept it as inevitable? – Circle of Clackamas
A: Weeds generally enter the lawn on occasion, ie when the lawn canopy is thinning due to lack of nitrogen, poor or infrequent mowing, disease or insect damage, lack of water and seeds blown in from around your property or ornamental beds. Once weeds are established, they can spread faster due to the proximity to your lawn. Clover is no different in terms of penetrating your lawn, but has the added benefit of being able to fix nitrogen from the atmosphere and growing laterally. It also produces seeds at low altitudes, often below your mowing height, so the seed heads aren’t always mowed off. For these reasons, clover can spread quickly once it gets into your lawn, especially if your lawn isn’t fertilized.
Read advice on clearing clover from OSU Extension Lawn Specialist Brian McDonald
Q: I bought a Supersweet 100 cherry tomato plant. Can I grow this in a 5 gallon bucket with stakes/support? Information online says they grow up to 5 feet. I have never successfully grown my own tomatoes.
And one more question: Why don’t seed and plant labels include how deep the roots grow? I’m told how high and how far apart they should grow, but not how deep the soil needs to be. Is there somewhere to get this information? – Multnomah County
A: You can successfully grow this tomato in a 5 gallon bucket. When planting you should pluck off any side branches (leave the top few inches) and basically plant the whole plant with the current root system deep in the bucket so your start is just the top few leaves and a few inches tall . All of these small hair-like structures on the main branch develop into roots and provide a good system for taking up water and keeping it stable over the summer.
Read more of the advice from OSU Extension Agricultural Outreach Coordinator Chrissy Lucas here.
– The Oregonian/Oregon Live