Garden Doctors: Growing drought-resistant yarrow

A.J. asks: I have been trying to research yarrow because it seems to be an outstanding plant that can be included in a low-water designed garden and one that deer seem to avoid. Can I grow yarrow easily from seed?

Yes, you can grow them from seed, and now is the time to plant the seeds since the soil has adequately warmed up. Check the germination time on the seed packets because some yarrow varieties will take longer to germinate. The Achillea millefolium with its ferny foliage is available in many colors, and the pastel shades are always popular. Prepare the soil by removing all weeds, loosen the soil to several inches deep, and then smooth out the surface. Scatter seeds on the soil, rake lightly and water gently. (Do not cover the seeds with soil.) I have found that covering the seed bed directly with a lightweight row cover and gently sprinkling water over the top of the row cover will keep the soil moist without drying out readily, doesn’t disturb the surface seeds, aids germination and prevents the birds from dining on the seeds.

Yarrow will thrive in sunny locations and are considered somewhat drought-tolerant once established. Water once a month in coastal areas and twice a month inland. Unfortunately, deer have been seen munching on some of the cultivars; there is never a guarantee about their eating preferences. On a more positive note, yarrow attracts butterflies.

Avoid high-nitrogen fertilizer, as it encourages lanky, sprawling growth as the plants mature. Clumps should be divided every three years when new growth begins. Achillea millifolium does self-sow, and it can become invasive and a nuisance in well-watered soil, so use drip irrigation. Remove spent flowers before they set seed.

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Pamela asks: The past few days, the deer have devastated all of our roses, the grapevine leaves and the vegetable starts we recently planted. I had caged a tomato and the deer reached inside and managed to pull up the entire plant! I am heartbroken, and now I am told I should start spraying a repellent on a weekly basis. Is one repellent more effective than another? It is strange that they had left our garden alone until now. We do have a low fence and they obviously are jumping over it with ease.

Deer are creatures of habit and continue to use their comfortable pathways. We don’t know, but perhaps they are foraging for easy food and preparing for the drought.

You have a low fence, and yes, that is easy for them to jump. Six feet is the recommended height to exclude them. Another effective method is to build a double fence, as used in vineyards and by people who do not want a high fence enclosing their property. Basically, you build two low fences with a distance of 3 feet between them. When the deer jump over the first fence, they will have to land between the two before the next jump or be able to clear the entire distance of the two fences. It is an expensive solution. YouTube also has some creative solutions to the problem; some work and some don’t.

Spraying a repellent is effective, and changing the product every few weeks prevents the deer from getting too familiar with the scent. The repellent is supposed to confuse their sense of smell that warns them of predators. I like the Plantskydd repellent, and it will remain effective after irrigation or rain. The product consists of dried blood, vegetable oil and water, and is OMRI listed. Another product is Liquid Fence, but deer seem to become immune to that after a while and will then continue to browse. Another product that is effective is Repels-All; its ingredients are dried blood, putrescent whole egg solids and garlic oil. Or you can make your own concoction, less expensive and many times equally as effective.

Unfortunately, neighborhood deer are becoming less worried about humans harming them and are acting like pets, especially those being fed. Of course, this just encourages more urban garden browsing. Pet dogs will keep deer away, especially larger dogs that have a loud bark.

Lastly, the University of California Cooperative Extension has a publication titled “Wildlife Pest Control Around Gardens and Home.” Contact the Cooperative Extension office off Airport Boulevard and ask for purchasing availability. The publication will tell you everything you want to know, plus more.

Dana Lozano and Gwen Kilchherr are garden consultants. Send your gardening questions to the Garden Doctors at pdgardendoctor@gmail.com. The Garden Doctors can answer questions only through their column, which appears twice a month in the newspaper and online at pressdemocrat.com.