Showing posts with label Roses. Show all posts
Showing posts with label Roses. Show all posts

Tuesday, February 1, 2011

It's February and Time to Prune Roses

'Joseph's Coat' rose

Ask rosarians around here and you will find out that February is the month to prune roses. Exactly when in February is a matter of opinion. Some people do their pruning around the first of the month. Others wait for Valentine's Day or Presidents Day. Others won't touch their roses until the last days of the month.

Why does it matter? Pruning stimulates growth. Plants respond to being cut back by releasing growth hormones and new shoots follow soon after. This new growth is tender and very susceptible to cold damage. A late, hard freeze will kill the new growth and possibly the entire plant. Therefore, you want to hold off until you are reasonably sure the danger of a freeze is past.

Beyond the question of when to prune roses, there's the question of how. The answer is complicated because there are several different types of roses and they are pruned in different ways. Hybrid tea roses are cut back to about 18", shrub roses are pruned to shape them and climbers are pruned primarily to train them onto a structure. Rejuvenating old roses requires yet another technique. As always, I refer you to the book, Pruning and Training, for specific directions.

If you live in the Seattle area and want hands-on instruction, consider attending Plant Amnesty's rose pruning class on February 13. The cost is a reasonable $15 for non-members (less for Plant Amnesty members and horticulture students). You'll learn the proper way to prune your roses and have a chance to ask questions before trying this at home.

Keep in mind that rose pruning varies considerably from region to region. What works in the unique climate of the Northwest is not applicable to other parts of the country (or world for that matter). If you live outside the Puget Sound region, check with your local horticulture professionals for advice.

Monday, October 11, 2010

A Rose Is a Rose, Is an Apple, Is a Berry

Botanically speaking, roses belong to the Rosaceae (ro-ZAY-cee-ee) family. This is a huge family, encompassing over 2800 species of plants, including fruit trees, shrubs, berries and, of course, roses. There isn't a single set of characteristics you can use to identify all members of this family, but there is one identifier that several genera share: a star-like shape at the base of the fruit.

Here you see cotoneaster berries with those distinctive "stars" on the bottom.

Once you know to look for this characteristic, you will begin to recognize other relatives in this family. These include: Hawthorn, Pears, Rowan, Cotoneaster and Pyracantha.

Fall is the best time of year for this, of course, because that's the season when these fruits are ripe.

Here you see the "star" at the base of an apple, another rose relative. You'll find stars on the bottoms of pears, too.

And notice the stars on rose "hips" this time of year.  (Pictured here are Rosa glauca hips.)

Beyond this bit of botanical trivia, it is useful for gardeners to be aware of these family relationships. Many members of the Rosaceae family share a susceptibility to fungal diseases, such as black spot on roses and scab on apples. Knowing this, a gardener can be prepared to take steps to keep plants healthy, which might include the use of dormant oil sprays, good sanitation practices and companion planting with members of the allium family (garlic, chives, onion, etc.)

So there's your mini botany lesson for today. Now go out and do your own version of "star search."

Tuesday, June 15, 2010

Keeping the Bloom on Your Roses


I've been noticing that the roses in West Seattle gardens are particularly beautiful this year. This is worth noting because the climate in the Pacific Northwest is not the best for growing roses. Roses love sun and we don't get a lot of it. Our cool, damp days are better suited to the growth of fungal diseases, like black spot, that love to build colonies on the leaves of our rose plants. 
(Some roses more suited to our climate than others. If you want to know more about them, I recommend Christine Allen's book, "Roses for the Pacific Northwest.")
So why are our roses looking so good this year? I suspect that it has to do with the extra rainfall we've had this year. Our usual rainfall pattern is that we have adequate rain to keep gardens looking lush through the month of May. In June, we often have a lot of cloudy days, but not very much rain. Gardeners are fooled by the cloudiness into thinking the garden is getting enough water, when that isn't necessarily the case. Particularly with roses, which are greedy on all fronts: they want lots of water, sun, and nutrients. 
So far this year, we have had three times the usual amount of rainfall for the month of June. This has had the effect of extending bloom time for lots of spring flowering shrubs and perennials. Roses, most of which are at the beginning of their bloom season, are getting off to a healthy, well-watered start this year. If you want to keep the bloom on your roses throughout the summer, I suggest that you consider following up with a good fertilizing routine. Ideally, that routine would have started months ago, but whatever you do to feed your roses from here on out will be rewarded.
Here is a 4-Step feeding program for roses that was given to me years ago by a rosarian with a passion for both beautiful roses and keeping hazardous chemical use to a minimum. He has long since sold his nursery and moved out of the area. Thanks, Robert, wherever you are! 
If you are fertilizing your plants for the first time in June, skip step one and continue from there.

  1. In February, March or April, apply 1 cup of superphosphate to each rose in your garden. Superphosphate works better than bone meal because it breaks down faster. It builds strong root systems and improves the rose's ability to flower repeatedly over the summer. It also costs less. Use it only once a year.
  2. Apply 1 cup of alfalfa meal of 2 cups of alfalfa pellets to each rose in March or April. Some rosarians repeat this application in June. Alfalfa releases nitrogen slowly and releases an enzyme that dramatically increases the rose's feeder root system. This means that the plant can make better use of available nutrients in the soil, as well as the fertilizers you give it.
  3. Starting in April, as the soil begins to warm, apply 1/2 cup of granular 16-16-16 fertilizer, and re-apply every 4-6 weeks. Your last application should be in August. (As with all granular fertilizers, water well after application unless you have adequate rainfall to dissolve them.) This step is the core of your feeding program.
  4. Apply Epsom salts (magnesium sulphate) to your roses to stimulate new, larger canes and to enhance flower color. Use 3/8 to 1/2 cup per rose in May or June. Magnesium sulphate, combined with a complete feeding program, does a good job of rejuvenating old, tired roses. 
Along with a good feeding program, be sure that your roses get plenty of water during dry spells. They aren't as thirsty as lawns, but still - they aren't drought tolerant. Also, roses need lots of sun. There are a few, rare cultivars that will grow in shade, but most will be leggy, buggy and fail to bloom unless they are in full sun.

Be aware that even under the best circumstances, there are some rose varieties that are hopelessly susceptible to problems. If you have them in your garden, you might be better off replacing them with hardier cultivars. Ask at West Seattle Nursery for suggestions. There are lots to choose from. Enjoy!
Do you need a Horticultural House Call? For more information or to make an appointment, please email me.