Way With Roses
By Doug Whitt
From The Charlotte Rosebud, May-June, 1999
The temperature swings of March and April usually result in mood swings of equal intensity in the serious rosarian. May, on the other hand, generates a more favorable setting in the garden for growing the Queen of Flowers. Don't we wish that all months were as May!
We are fortunate to live in an area of the country that is blessed with a long growing season as well as only a brief period of temperatures in the range that could produce harmful effects to rose plants. The benefits of seasonal cold weather at least balance the consequences of none at all... The rosarian gets a short break from a weekly regimen of maintenance, while nature attempts to purge the garden of parasitic annoyances. Perhaps this summer we can enjoy a more favorable balance of less heat and humidity than we had to tolerate last year. Oh well, I can dream, can't I?
The excitement of the roses now coming into bloom dispels any anguish that one may have undergone as the season has progressed. The graceless, unsightly objects with menacing thorns and disorderly growth that yielded to our pruners just short weeks ago are now resplendent with breathtaking buds and blooms worthy of any occasion.
With the area rose shows in progress throughout May and into June, why not share with the public some of the glorious culmination of the first bloom cycle. Most show locations are only an hour or two away, and just participating is an award unto itself. Ribbons and honors are an added bonus that is the compensation for an endeavor well done, and friendships made with other rosarians sharing the same passion of displaying our national floral symbol can last a lifetime.
If you are interested in adding some new varieties to your garden, the rose shows are the ideal place to help you decide on which ones to obtain. Make notes of your own first impressions as well as comments from the grower, and inquire as to the source of the plant if possible. Then, when the rose catalogs are available next fall you can order based on first-hand observations rather than from pictures in a book.
Rose garden tours are another source of beneficial information about roses that grow well in our area. Make an effort to participate in an out-of-town garden tour this year as well visiting local gardens. My garden is always open, and this year I am planting many of the new roses just coming onto the market. I enjoy the anticipation of a new variety blooming in my garden, and this year I should be ecstatic if I can keep the rabbits in check... They love my roses too!
To continue to enjoy the full beauty and maximum production from the garden the remainder of the season, the rosarian must administer the necessary protection from pests as well as the watering and feeding on a regular schedule. Certain diseases are inherent in roses, and if ignored, they will not just go away.
All of us as rosarians are interested in the latest happenings in the world of roses. This interest ranges from the newest varieties on the market to the next level of safer pesticides... from the most recent fertilizer introductions to the ultimate in spray equipment. By being a member of the American Rose Society we can be privy to the wonderful world of roses and be a part of the dynamics that drive our great hobby. Each issue of The American Rose magazine always contains something new and educational, and the monthly magazine is only a portion of the benefits an ARS member enjoys. If you are not a member you are missing out on a vast source of pleasure relating to the hobby of growing roses.
Let us see what we should be doing in the garden now.
Rising temperatures this month quicken the pace for growth that should signal to the rosarian a need for a similar intensification in overall awareness of the plants' needs. The pests that prey on roses seem to increase proportionately to the rise in temperatures. Now, and for the balance of the growing season, a systematic approach to caring for the plants will pay dividends of more quality blooms and stronger overall growth. I use a calendar to remind me of application schedule dates as my memory is not as good as it should be.
It is difficult to say which garden activity is the most important, but the weekly water application rates right up there. For the small garden, a hose-end water wand is adequate, inexpensive, and ideal for watering in fertilizers and soil additives. For the larger garden, the rosarian may benefit from any of a number of watering systems that simplify this task. The water requirement this month will be at least one inch per week (about seven to ten gallons per plant depending on the spacing between plants), and any rainfall should be included in the total. I like to water on the same day of each week, and I schedule each application the day prior to the weekly spraying of pesticides. This assures plenty of moisture in the plants' foliage and reduces the incidence of spray burn to the new tender growth.
If you are not using the nine-month formulation of plant food we applied in March, each monthly feeding of granular fertilizers can be coordinated with the watering schedule. Roses are heavy feeders at this time of year, and a constant supply of food should be available in the root zone. Each application must be watered in thoroughly. Whether of an organic or an inorganic source, the nutrients must be in a soluble form to be usable by the plant. About 1/2 cup of 10-10-10, per plant, per month, scattered out to the dripline should be adequate in the small garden. For the production of larger, exhibition size blooms, a soil analysis can result in a fertilizer being formulated to meet the specific needs of a particular garden.
You have read my comments for years concerning pest control, and it is just as important today as it was 15 years ago. The specific spray materials may have changed in some instances, but the need to protect the plants from insects, mites, and fungus diseases has not. If one hopes to maintain quality blooms and plants throughout the active growing season (through October in our area), some protection is a necessity. As with watering and feeding, this protection should be administered on a systematic basis every seven to ten days.
In my garden I use a water wand, constructed specifically for blasting mites off the foliage, as a first line of defense against spider mites that may invade the garden (these wands are available from firms that advertise in the pages of The American Rose magazine). I also apply Avid (1/4 tsp. per gal.) at two-week intervals to have a barrier in place before a mite colony can take up residence. Graying, listless foliage on the lower portion of the plant is a sure indication that the mites are actively at work, and especially if the undersides of the leaves have a salt and pepper appearance as well as webbing. Immediate action is called for to disrupt this unwanted colonizer. The underside of the foliage should be the target of a forceful spray of water from the wand to dispatch this pest, and a follow-up application in four days to eliminate any that may have hatched from existing eggs that survived the first treatment. Follow this second spraying with an application of Avid as soon as the foliage has dried.
With the warmer weather, blackspot now becomes the major fungus pest and with the removal of Triforine from the market we must find another product for our primary control (Funginex, a weaker formulation of Triforine is still sold). I will be using Clearys 3336F this year, alternated with Daconil or Maneb, and applied as instructed on the container. Once blackspot gets established it grows internally in the foliage cells just under the surface, and I know of no fungicide that will kill the "fungal haustoria" once they have sealed themselves inside the leaf cell. This is why it is important to have a barrier on the surface of the leaves and canes before the fungus arrives. Any infected foliage should be snipped off and replaced in the trash as soon as it is spotted.
Powdery mildew is not as prevalent during the warmer period of the growing season, but it still will emerge from time to time. The new, tender growth is the most susceptible and should be protected during periods of cooler, cloudy days. I use Rubigan for this protection as instructed on the container.
Insects of some sort are always present in the rose garden. There are the "bad guys" and there are the "good guys", and since an insecticide cannot distinguish between the two, I do not include it now in my weekly spray program. I prefer to apply Orthene, Diazinon or Malathion on an "as needed" basis using a one-quart plastic hand sprayer and applying only to a problem area (mix as instructed on the container). Thrips are usually the most troublesome "bad guy" at this time, and a misting of the flower buds at two-day intervals as soon as they begin to show color in the opening bud should result in damage-free blooms.
If all of these products are confusing to the beginning rosarian, and you have a small garden of say, ten plants or less, there is a product from Ortho Rosepride Orthenex, formulated for use in the small garden that you might consider for use. It contains a fungicide, insecticide, and a miticide. For it to be effective, though, it too should be applied on a regular schedule as instructed on the container and coverage of both the top and bottom surface of the foliage is essential.
The mulch on the rose bed contributes greatly to the quality of blooms grown and should be maintained to a depth of two or three inches. I like to use pine bark and pine straw, but there are many products that are suitable as long as they are free of weed seeds and porous to allow entry of water and oxygen. The material should be aged, not green, or it will compete for the available nitrogen in the soil as it breaks down. Do not cover the crown of the plant with mulch during the active growing season, and keep all leaves and debris removed as soon as noticed.
The act of pruning begun in March will now continue in a more subtle manner as we remove the spent blooms (deadheading) at the end of the first bloom cycle, and the remainder of the growing season. Removing the matured bloom petals before they fall into the mulch is a "no-brainer"... I'm getting too old to crawl around in the mulch removing this possible haven for insects and disease. At this time of year I cut back to the first five-leaf leaflet, saving as much of the cane and foliage as possible. The result is more shade onto the rose bed and a little cooler soil temperatures during the heat of summer. Seal all cuts to major canes to discourage cane borers.
As the new growth begins for the second bloom cycle, keep an eye out for blackened tips at the top of the new growth. There are various budworms that will attack the newly forming bloom buds, but the most menacing is the rose midge. At only 1/25" in length, it certainly can do a lot of damage in proportion to its size. Diazinon granules scattered under the infected plants and to an additional two or three feet past the dripline, will dispatch the developing adults as they emerge from the soil. A follow-up application in about a month may be necessary if the infestation is severe. Follow package instructions. If you notice blackened bud tips, reprune to a strong five-leaf leaflet to encourage new growth.
I find that in my garden, the beginning of the second cycle is also the most active period for production of new growth in the form of basal and low lateral canes. These canes represent the future of the plant, and I will tie them to a stake to prevent high winds from breaking them off before they have hardened (usually after one cycle of bloom). Stakes in various lengths are available at most garden centers, and discarded nylon hosiery is excellent for tie material.
The increasing temperatures now mean a greater need for water, as the plants will lose more to transpiration, as well as to evaporation from the soil. I like to apply about two inches per week now, and water at three or four day intervals with one application on the day before my scheduled pesticide application. Keep the mulch on the rose bed to a depth of two or three inches to help preserve the soil moisture.
Make the monthly feeding of granular food if not using the 9-month slow release type. During the heat of summer, some rosarians prefer to divide the monthly allocation in half and apply at two-week intervals to keep a more constant source of nutrients available to the root system. Water in thoroughly, and try to coordinate each application with the scheduled weekly watering program for convenience sake.
Blackspot and spider mites are always lurking, just waiting for us to slacken our guard against these pests. Follow our instructions for last month in applying both a fungicide and a miticide, and keep in mind the importance of doing it on a systematic basis. Thrips will still be the chief nemesis of opening flower buds, and a misting with an insecticide at two or three day intervals should keep the petals free of the brown spots that thrips cause.
The first or second week in June in the Charlotte area bodes annoyance, grief, anxiety, (insert your own adjective here), for most rosarians as well as gardeners in general. It is time for the annual invasion of Japanese beetles. Some years their numbers are light, while other years the hordes just keep coming. The first few years after they arrived in our area I would spend much time in trying to keep the plants free of this pest. I soon discovered that plants that had been cleared of beetles by noon would again be covered by 5:00! 1 also observed that although they were an unsightly mm, the harm they did to the plants was not irreparable, and that the plants could cope with the intruders better than I could. I no longer do battle with the beetles except to protect a few blooms to cut for bouquets. The more menacing pests at this time are blackspot and spider mites, and they will not just go away like the beetles do in six to eight weeks after their appearance.
If you are determined to skirmish with the beetles, any good all-purpose insecticide will kill the ones that come in contact with it. A few drops in a plastic bowl half-filled with water results in a one-way dip for the bugs. The insecticide Sevin, in liquid or powder form, is effective, but will dry out the foliage if not hosed off weekly and then reapplied. Beetle traps will attract additional beetles to the garden, so if you decide to use them, install them as far from the roses as possible - maybe on the neighbor's property. Milky spore disease will control the grubs in the soil, but widespread use is required for it to be effective, and it is expensive. Mother Nature has been kind, with the beetles arriving just as the heat is reducing the size of blooms and vivid colors, and they depart just at the time for our pruning for the fall bloom cycle. By then there will hardly be any sign of such a savage invasion.
New growth on the plants is now being produced at an accelerated rate due to the higher ground and air temperatures. The blooms have fewer petals and the form and coloring is not what we were seeing in the garden two months ago. This is normal. Ideal temperatures for growing quality roses are highs from 7O degrees to 85 degrees and lows in the mid 5O's. We will not see them again until fall. In the interim, we must keep the plants growing vigorously and disease-free to be able to enjoy the bounty that will be there in late September and into October. If you take an extended vacation during the summer, ask a friend or neighbor to tend the roses until your return.
Hope you have a nice summer. Enjoy your roses.