Roses The Straight Scoop Part 4 - gardening

Flower & Garden Magazine, July, 2001 by Ann Hooper

SUMMER CARE FOR YOUR ROSES

Many gardeners believe that sad-looking rose plants at midseason are just the price you pay for the fabulous blooms and glorious foliage in the spring.

Roses may not be as easy to care for as impatiens, but they're not hard either, and with a little effort, you can have wonderful flowers and foliage all season long.

Today, it's easier than ever before to have pest-and-disease-free plants and perfect blooms from early spring until late fall. All you need are some really good fertilizers, a few good spray materials, lots of sun and water and a little common sense.

Roses are amazing plants that are just itching to perform for you. As you know, they are one of the very few perennial plants that bloom continuously throughout the growing season. In temperate climates, roses, if you let them, would grow and bloom all year long, expending huge amounts of energy and diminishing their life span. In these warm areas of the country, roses must be forced into dormancy during the coolest season to prevent them from growing themselves to death in three or four years.

We'll talk more about forcing dormancy later in the season, but the point is that rose plants will go to great lengths to grow for you, so it's important that you do your part to help them along. There are roses in my garden that are more than 20 years old and are still going strong. Many varieties of roses that you plant now, if cared for properly, will still be around to delight your great-grandchildren.

* FERTILIZING

As we've discussed in previous articles in this series, good soil is important to the health and well-being of roses. Planting soil should be amended with slow-release organic nutrient sources, such as bone meal, blood meal, compost and composted manure. But the plants use these materials rapidly, and it's necessary to replenish them on a regular basis. Roses are heavy feeders, and while the organic materials are vitally important, they are rarely enough to provide the plants with all of the macro and micronutrients needed.

An effective fertilizer regimen will not only ensure a constant supply of nutrients throughout the season but will provide all of the elements roses need to perform at their best. We always think of plants as requiring the usual N-P-K macronutrients (nitrogen, phosphorus, and potassium), but we sometimes neglect to provide the many micronutrients roses and other plants need. These include iron, calcium, sulfur, manganese, molybdenum, zinc, boron, and copper. Carefully formulated organosynthetic fertilizers, such as Peters and Magnum Grow, include chelated micronutrients that can be easily used by the plants.

Roses and other plants use these elements as they are broken down into forms that the roots can take into the plants' vascular systems to promote photosynthesis. The elements are broken down by chemical changes having to do with positive and negative ions (far too technical for my small mind) and by microbial action in the soil. These good bacteria must be replenished often by the addition of a variety of organic materials, such as fish emulsion, liquid seaweed, compost and composted manure. (The bone and blood meals should only be used at planting time because they don't travel in the soil when applied to the surface and provide no benefit at this point.)

So, a good fertilizing program will include both chemical and organic fertilizers applied on a regular schedule.

Of course, the good stuff you give your roses can also lower the pH of the soil, so regular applications of lime may be necessary to keep soil in the best range for roses--5.8 to 6.3. Regular dolomitic limestone--the stuff you put on your lawn--works great, but it takes six months to provide any benefit to the soil. As well, lime doesn't travel in the soil, so it must be applied well below the surface, near the roots where it's important that the pH be in the correct range. Using a long dowel, you can make several holes in the soil at the base of each plant and fill the holes with lime.

Other forms of lime, such as granular lime and hydrated lime work faster, but must be applied in the same way. Liquid horticultural limestone, such as Limestone F (for "flowable"), can be mixed with water and applied to the surface of the soil. It is very fast acting, providing maximum benefit in just two weeks.

Another excellent material for raising pH is wood ashes. I clean out the fireplace a couple of times a year and save the ashes in a sealed container for application to the garden in the spring. Wood ashes have an off-the-scale-high pH and must be applied to the surface of the soil very sparingly so as not to raise the pH too high or too rapidly or burn delicate feeder roots.

For people who grow roses, a home pH meter or pH testing tape is a great help in maintaining the perfect pH at all times.

Fertilizers may be applied much more often than you might think. Some rosarians feed their roses something nearly every day. Some feed once a week. But that's not to say that you can't have perfectly wonderful roses if you feed once a month. Frequent fertilization means using a wide variety of chemical and organic fertilizers so you give your plants something different each time you feed. Fertilizing monthly requires the application of a mixture of fertilizers composed of both organic and chemical products.