This daphne may have heat damage from last year's heat spell.OSU Extension Service

Spring is on the way and that means gardening season. You may have 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, type it in and the county where you live. Here are some questions asked by other gardeners. What’s yours?

Q: My daphne is sad. I’m not sure why. Are you able to help identify what to look for?

It’s a year old, planted last February in part shade, in a bed that was turned grass 1.5 years ago, and mulched in the summer.

This spot gets dappled sun with mostly shade, and full sun for maybe an hour a day. My neighbor has a mature one about 60 feet away (in full sun) that’s thriving. Not sure what might be happening in my yard. – Multnomah County

A: Your daphne was damaged last year during our several heat spells, with possibly most severe damage occurring in late June and early July when a heat dome stressed everyone and everything. At that time, the daphne hadn’t yet extended its roots into the surrounding soil, so was unable to remain fully hydrated.

Even though the daphne was in light shade and received minimal direct sunlight, the excessive air temperatures were adequate to damage the most exposed areas of the leaves. On the damaged leaves, the thin gray portions reveal where the worst of last year’s damage occurred. There, the excessively hot air killed plant cells. Months later, the damaged cells began to flake off, such that the gray areas of dead cells are now skeletonized. And when we look still closer at the damaged leaves, the green portions of the leaves are mostly intact when compared to the (normally) yellow portions. Fortunately, that greenery will help the shrub recover this year.

--Jean Natter, OSU Extension Master Gardener diagnostician

Garden mulch can be raked away from proposed planting areas. File photo. Saed Hindash | For lehighvalleyl

Q: Some friends helped us rip out a section of our lawn, and we are going to plant the area (about 19 feet by 6 feet) with native plants this spring.

However, I’m ordering plants from a local, affordable pop-up native plant provider, and they won’t be ready for pick-up until April 8. What should we do with the bare area in the meantime?

Eventually we plan to have a bunch of mulch delivered to spread around the area. Should we wait until after putting these plants in in early April to put down the mulch, even though some weeds will likely sprout in the six or so weeks between now and then? Or should we get the mulch now and spread it, even though we’ll need to dig down through it when we plant?

We do plan to get our more major plants before then (specifically, we plan to get a red-flowering currant, a ceanothus, and two ‘Wayside’ manzanitas and plant them at the beginning of March), so maybe a compromise would be to wait until after we plant those things to put down the mulch and then dig through it to plant the smaller things we’re getting?

I’d love to hear any advice you have. – Multnomah County

A: I assume you are planning to use an organic mulch such as arborists wood chips rather than rock or synthetic mulches.

We recommend applying three to four inches of mulch. Any more than that can impede moisture from permeating the mulch.

Keep the mulch several inches away from the trunks of any trees or shrubs. Personally, I would put the mulch down as soon as possible. This will not only prevent weed seeds from germinating but will also help to keep the grass from regrowing.

When it is time to plant, use a garden rake to clear the mulch away from the planting site for each tree or shrub. After planting, the mulch can be raked back into place.

– Lynne Marie Sullivan, OSU Extension Master Gardener

Q: I have this fortnight lily that I have had for four or five years. It has always been in great shape and blooms every year. I have it in the front of my house which faces the south. Just recently during this winter it has turned to white with black spots.

I have watered it a few times this winter since it is technically under my roof eaves. Can you tell me what’s going on with this plant? If I cut back the entire plant will it grow back? – Washington County

A: Your fortnight lilies (Dietes vegeta) are evergreen plants that grow from corms and are said to be hardy to 25 degrees. As such, they could be considered marginal here in the Northwest. Unfortunately, it appears that the entire potful died this winter. All the foliage has been affected; I don’t see any green.

It’s true that occasional watering helps plants survive low winter temperatures because a moist rootball freezes more slowly than a dry one. Even though you may have watered the pot this winter, you may have inadvertently missed a time when the rootball was dry during one of our cold snaps. (Just how cold it was at your place depends upon several factors, including the elevation.)

Then, too, it’s my experience that, in containers, this species tends to peter out after about five years, perhaps due to rootbound conditions. Although I haven’t yet tried them in the garden, I suspect they might thrive there for a longer time. In any event, I suspect you received your money’s worth from the original corms. So, because fortnight lilies are such charmers, consider planting more of them. – Jean Natter, OSU Extension Master Gardener diagnostician

Q: I just relocated to Beaverton last spring, and am having problems controlling a weedy grass. It takes over good turf, and bare spots, and seems to also grow year-round, rather than just in the summer. Would you be able to identify this and suggest how to control it? – Washington County

A: The weedy grass is annual ryegrass, sometimes called Italian ryegrass. It often comes in seed mixes, sometimes intentionally and sometimes as a contaminant. Since it is an annual plant, it will die by itself next summer. If you are overseeding your lawn, be sure and check the bag carefully to see if annual or Italian ryegrass is listed on the label. If it hasn’t been and it is still showing up after seeding, then I would try to find a higher-quality grass blend. You can buy directly from some seed companies if you purchase online.

Oftentimes seed companies will mix annual ryegrass with perennial ryegrass and other lawn grasses as a way to reduce the cost of the seed sold to homeowners. Annual ryegrass is much less expensive to grow than perennial ryegrass, I think because the seed yields are much higher for the same acre planted. Additionally, for less expensive mixes that are not certified, seed companies do not clean the seed as thoroughly and often end up with other seeds in the bag that include annual ryegrass. – Brian McDonald, OSU Extension turf expert

A diagram of recommended cuts for a Japanese maple.OSU Extension Service

Q: We have a Japanese maple with a complex shape that we would like to prune to keep happy and healthy. It looks like the main trunk was cut back a long time ago and there have been side shoots that have established. One of them is growing toward the house and we are thinking it may be best to remove it. Would this be OK for the tree? It is growing at a funny angle. – Marion County

A: You should be able to prune off the branch marked in your photo. I have attached a diagram showing where I think it should be cut, however, I cannot see the backside to determine if the branch bark is included (attached) to the other branch. You will want to avoid cutting into the branch collar (i.e. the place where the branch widens at the trunk) or where the bark is included in another branch.

Your goal here is to create the smallest wound possible. We no longer recommend painting or treating the wounds on trees. Allow the cut to heal naturally. The best time to prune is now, before the tree begins to bud out. – Lynne Marie Sullivan, OSU Extension Master Gardener

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