Care for roses now pays off later

By SUSAN BOESCHEN UC Master Gardener

Most mornings this month, you’ll find me in my garden feeding, grooming and generally trying to coax my roses into putting on a superior floral extravaganza. My garden will be on the Napa County Master Gardeners’ Garden Tour on June 3, so the pressure is on to get my 350-plus roses to look their best when visitors arrive.

Roses have been falsely accused of being the high-maintenance prima donnas of the garden. If you select disease-resistant varieties to begin with and prepare the soil well at planting time, they are actually an easy and rewarding plant to grow. Now is the time to take a little extra care with fertilizing and mulching in order to guarantee masses of gorgeous blooms later.

Fertilizers provide the minerals needed for plant growth and come in a variety of organic and chemical forms. There are probably as many ideas about how best to feed roses as there are rose growers. But the roses don’t really care what form their food comes in as long as they are fed, so the choice is up to you.

I use only organic products in my garden as I like the idea of enhancing the soil when I fertilize. March is a good time for your first fertilizer application of the year. Even if you use chemical fertilizers later in the season, it’s a good idea to make the March application with a dry organic product. The organic fertilizers will remain dormant until the soil warms up and the plant roots are able to take up the nutrients. Liquid fertilizers and most chemical fertilizers act on application and may leach out of the soil before the soil temperature warms sufficiently.

I start by raking a very shallow trench around the drip line of the bush, being careful not to disturb the roots. In the trench, I put a balanced dry organic rose fertilizer, following package directions, and a two-pound coffee can full of alfalfa meal or pellets per bush. As alfalfa disintegrates, it releases an alcohol called tricontanol which stimulates rose growth. It also contains low doses of minerals and trace elements. Alfalfa is inexpensive and can be found at most feed and agricultural product stores.

Other dry organic products you might consider include aged chicken or turkey manure, blood meal, bone meal, cottonseed meal and fish and seaweed meal. I’ll top this all off with a couple of shovels full of compost for good measure. Many rose experts advocate adding Epsom salts (magnesium sulfate) to the feeding program to stimulate growth. However, University of California research does not support this practice as most soils in the Napa Valley are already high in magnesium.

My plan is to fertilize again in May after the first bloom cycle, then again, lightly, in July, with a final feeding in September. This is an ambitious feeding schedule. I admit that I don’t always do this much, and the roses still manage to bloom.

It is best to alternate various fertilizer sources throughout the year. For the later feedings, I like fish emulsion and water-soluble kelp products that I spray on as a foliar feed. You might prefer a chemical fertilizer, which is fine as well. To make sure that the fertilizer doesn’t burn the roots or the leaves of the plants, water the day before you fertilize, and then water the fertilizer in well immediately after application.

March is also a good time to apply mulch to your rose garden. Mulch is a material placed on top of the soil to retain soil moisture, reduce weed growth and keep the soil cool. Compost, aged manure, bark chips or even shredded newspapers covered with bark are all good mulches. You can also use straw, hay, wood chips, leaves and grass clippings if you compost them first and add extra nitrogen. Apply a two- to three-inch-thick layer of mulch, and remember to keep the mulch three inches from the base of the plants.

If any of this routine seems overwhelming, consider attending the free Master Gardener workshop on “Beginning Gardening” on March 10, at the University of California Cooperative Extension in Napa (address below). The workshop will be repeated on March 17, at Napa Valley College’s Upper Valley Campus in St. Helena. Call 707-253-4221 to reserve a space.

I’ll look forward to seeing you in my garden on June 3, for the garden tour. The tour benefits the Master Gardeners’ community education programs in Napa County. You’ll have the opportunity to visit three gardens in St. Helena and three in Calistoga, all owned by Napa County Master Gardeners. For ticket information, visit the Master Gardener website at http://cenapa.ucdavis.edu and click on Master Gardener or call the ticket information number at 253-4147.

Napa County Master Gardeners (www.mastergardeners.org) are available to answer gardening questions Monday, Wednesday and Friday, 9 a.m. to noon, at the UC Cooperative Extension office, 1710 Soscol Ave., Suite 4, Napa, 253-4221, or toll-free at 877-279-3065. E-mail your garden questions by following the guidelines on Web site. Click on Napa, then on Have Garden Questions?

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