Gardening season has been put to bed for winter, but you may still 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 include the county where you live. Here are some questions asked by other gardeners. What’s yours?

Q: My rhododendron plants are showing brown edges on leaves with also some white discoloration. Is this a fungus? How should I treat it?

I haven’t had to water them since our rainy season began. I turned off the watering system probably late November or early December.

I have an automatic sprinkler system (above-ground hose) that is set to water the rhodies three times per week in the early mornings for about 15 minutes each time. Of course, we had that awful heat wave back in June that was a huge shock to all sorts of plants. It’s possible the rhodies got some of the leaf damage at that time. But lately I was shocked how bad they look now (although flower buds are starting.) -- Washington County

A: The affected leaves on the rhodies clearly show the following:

• Sunburn (the dead brown areas, most of which are marked with white, which indicates that dead cells are flaking off)
• Scorch from excess heat, but short of sunburn, which would present as purpling on high spots of leaves
• Brown leaf edges indicate a water shortage in the soil, most likely intensified by last season’s heat wave
• The rhodie in the photo is seriously affected by the lack of soil moisture. If rhodies are watered from the in-ground sprinkler at the edge of the bed, it is likely in an “irrigation shadow” where another shrub is blocking the spray.
• The good news is, though, that there is no disease, fungal or not.

Consider the following:

• Increase the depth of the wood chip mulch to 3-4 inches deep. (You can obtain free wood chips from ChipDrop.)
• Consider changing the irrigation schedule to once a week, or twice a month; then run the system long enough to moisten the soil to 12 inches deep. To determine how deep the moisture goes, probe the soil with a long, flat-headed screwdriver. It will easily penetrate moist soil but will stop abruptly if it strikes a rock, a large root or dry soil
• Consider how the scraggly rhodie could be irrigated more effectively, perhaps by trimming plants that block the spray, or supplementing with hand watering

– Jean Natter, OSU Extension Master Gardener diagnostician

Good lawn care is easy once you know the rules

Q: My backyard is spotty, uneven and could use some sprucing up. Can I just add some good compost or soil on top of existing grass and sprinkle some seed? I’m not looking for total redo, just a little help. It is a small yard, approximately 20 by 10. – Multnomah County

A: Consistent correct care of your lawn is a big step to improving the look and resiliency of the grass. Mowing, fertilizing and watering correctly are key, and easy to do once you know the “rules.”

Since your lawn isn’t in good shape now, rejuvenation is the term we use for fixing it without full replacement. “Now’s the time to spiff up ragged lawns” is an article published in August, but the basics are covered. The resource links in it are also useful, both written and video. Now, in winter, is not the time to take action. Instead, diagnose and plan your steps for warmer weather. The timing of planting and establishing interplanted grass is critical.

The diagnosis step will help you know if you’ll need to plan yearly over-seeding or if you can make changes to keep healthy turf longer. Is your lawn getting enough sun, for instance? – Jacki Dougan, OSU Extension Master Gardener

Why fight nature?

Q: I like a more natural look. Three years ago, I had the laurels pruned at the top only. They are now quite high and I was wondering whether it is OK to let them grow without pruning. – Multnomah County

A: There is no requirement to prune laurels, and some landscape experts recommend that they be left to grow into tree sizes, rather than “fighting nature” to try to convert them into hedges. Here is an OSU Extension article about them and their care. – Kris LaMar, OSU Extension Master Gardener