Way With Roses: July-August, 1999
By Doug Whitt
From The Charlotte Rosebud, July-August, 1999
This time of year tests the resolution of most practicing rosarians. The human body resists being subjected to 90 degree plus temperatures with the humidity in the same numerical range. The roses don't exactly flourish under these conditions either. Yet, if we hope to enjoy a bounty of lovely blooms that will arrive with the cooler temperatures of autumn, certain chores must be performed now. After all, it is summer.
Spraying in the early morning is more beneficial to the roses (as well as to the rosarian). Watering, feeding, mulching, and other duties too are better performed in the cooler morning hours. Early evening can be an alternative for those whose work schedule does not allow otherwise, but spraying at midday with the sun beaming down can produce spray bum to new foliage.
Keeping the plant healthy through the heat of summer is important not only for fall bloom production, but plants weakened by neglect may not survive the coming winter. Preserving as much foliage as possible now contributes to the plants' well being. I now still only cut back to the first five-leaf leaflet when removing spent blooms (deadheading). Harsher pruning will resume in mid-August in anticipation of the fall bloom cycle.
If your pest control program has been administered on a regular schedule, and you have used fresh (not outdated) pesticides, your garden should be free of serious unwanted disease or nuisance infestations. To keep it that way requires a frequent jaunt through the garden with a keen eye out for any unwelcome intrusion. Spotting a new growing colony of spider mites or a plant with an infection of blackspot can be dealt with locally before it has time to spread to neighboring plants.
I usually remove the bottom six inches of foliage from my plants with the pruners. I have found that this is the area where many pests first become established (the rabbits help with this foliage removal from time-to-time!). This also helps in getting better spray coverage to the underside of remaining foliage, which is where a majority of pest-related problems originate.
Visiting other gardens to see how various rosarians cope with the effects of heat can he beneficial. No two settings are the same, but shared experiences and ideas may help to improve your own garden. New varieties being grown elsewhere in conditions similar to your own can influence a decision on whether to obtain them for your own garden next year. (A note pad is an essential tool when making these visits - especially if your memory is like mine.)
Charlotte Rose Society activities during the summer provide the opportunity to meet other enthusiasts who share this great hobby. Talk of the hottest new variety, the latest in pest management, or the source of the ultimate organic food for roses are sure to make this sharing of experiences and knowledge a rewarding adventure.
A membership in the American Rose Society should be a high priority for the rose enthusiast. I have said many times before that I look forward to each issue of 'The American Rose' magazine. There is so much information in its pages pertaining to the entire hobby of roses... it's like a window into the heart of this dynamic pastime. Trust me, you won't regret joining the over 30,000 present members.
Let's look at what we should be doing now in the rose garden.
JULY and AUGUST
Since climatic conditions are similar for both months I will combine the "things to do" recommendations.
Keeping the plant healthy through the heat of summer is important, and preserving as much foliage as possible contributes to its well being. In fact, the good health of the plant through this exasperating time can be the difference in plants that will survive the coming winter and those that don't.
I cannot emphasize enough the importance of water during the summer. Water is an ingredient that must be available in the soil throughout the year in varying amounts depending on the season. In winter while the plants are resting, the turgidity of the canes is dependent on a lesser reserve of soil moisture. However, at this time of year the demand is at its peak as the plant seeks to replace moisture lost through transpiration as well as that which has evaporated from the soil being heated by the sun. If you have observed new canes drooping in the afternoon heat it is evidence that the plant is unable to extract enough moisture through the roots to keep up with that lost through transpiration. As evening arrives with its cooler temperatures, and with adequate moisture available, the canes will regain their rigidity. The aphorism of about 2' of water per week now is usually adequate. I like to water twice weekly applying l' (5 to 7 gallons per plant) at three or four-day intervals with one application made the day prior to my scheduled day to spray. Any rainfall will be included in the weekly total, and don't minimize the benefits of a mulch two or three inches thick on the rose beds.
The monthly feeding can also be coordinated with the watering schedule. One-half of the monthly food requirements applied at two-week intervals will help equalize the availability to the plant throughout the entire month. Heavy sustained rains of four or five inches or more (such as hurricane remnants or severe thunderstorms) may temporarily leach necessary nutrients out of the root zone. An application of a liquid food (Schultz, Miracle-Gro, Mills Easy Feed, etc.) will stabilize things until conditions return to normal. Having an organic food source in place since spring also helps minimize the effects of excessive rainfall.
Toward the end of July or by early August I like to supplement the regular feeding program with additional ingredients in anticipation of the fall bloom whose growth begins about mid-August. I feed one or two teaspoons of chelated iron (depending on the size of the plant) per plant for dark green foliage; two tablespoons of Epsom salt (magnesium sulfate) necessary for green pigment for chlorophyll and the process of photosynthesis. I mix both the items in water to apply. I also spread three or four tablespoons of 38-0-0 or 46-0-0 urea-form nitrogen (slow release) evenly around each plant out to the dripline, and use the above mentioned liquid mixture to water it in.
If you have been feeding monthly with a balanced granular food, make the final application of the season around the last week of August. This will sustain the plants through September and into October. We do not want to induce heavy new growth into late October that may be frozen before it has had time to properly harden.
Late summer is usually the beginning of the corn-earworm intrusion that can alter the quality, as well as the quantity of fall blooms. Multitudes of the brownish-gray moths flitting about the lawn and garden as one walks into the area is convincing evidence that the potential for concern is at hand. Control of these pests as soon as their activity is noted is important. Some rosarians use a 'bug- zapper,' an insect-attracting light that lures the moths into an electric grid, with limited success. I have found that most moths are active in depositing their tiny white eggs on rosebuds in the early evening and at night. In a day or two the eggs hatch into the larva stage (the same worm you may have seen in an ear of corn), and with a ravenous appetite begins at once to eat into the flower bud on which it was deposited. This results in damage to or loss of the small buds, or in the case of larger buds, unsightly holes in the petals as the blooms opens. I watch for the eggs on the growing buds, and mash them with my thumbnail. I have noticed the tiny white eggs will often be deposited two or three per bud, and the moth will at times move down an entire row of plants laying eggs. A bacillus (Dipel in dust form, and Thuricide in liquid form) will stop the larvae from feeding by paralyzing their mouthparts as they feed on the buds. Some damage will occur before they ingest enough bacilli to stop feeding.
Cucumber beetles (green with black spots) will become more prevalent as summer passes. They hide inside the opening flower buds and eat holes in the petals. Thrips are present in the opening flower buds at all times it seems, and a wide spectrum insecticide (Orthene, Diazinon, Malathion, etc.) applied to the opening buds at two or three-day intervals should control both these pests.
Powdery mildew, though not as much a threat now as blackspot, will occasionally occur on the new growth. Triforine/Funginex, Cleary's 3336, Rubigan, or Orthenex, applied per container instructions prior to infection should prevent an occurrence. In fact Triforine/Funginex or Cleary's 3336 as well as Orthenex provides protection against both powdery mildew and blackspot.
This is the prime season for spider mites, as they love the 90° plus heat. Since they usually begin colonizing on the bottom surface of the lowest foliage, the foliage removal I referred to earlier makes for a much simpler treatment with the water wand as well as application of a miticide such as Avid or Vendex. Here, too, prevention is the name of the game, so a constant vigil for any outbreak is necessary for a quick response.
Sometimes my maintenance recommendations may seem to be extreme, but as I have said before I grow my roses with the potential for exhibition in mind. You may be satisfied with less quality, but the healthier, disease-free your roses are, the more you will enjoy them and the experience involved in producing them.
With the area fall rose shows beginning in late September and continuing well into October, pruning should begin in August if one wants to compete. The many-petaled and slow-cycling varieties (Uncle Joe, Touch of Class, Lynette, etc.) I will begin pruning the second week of August, and continue through the lesser-petaled varieties until the first of September. Pruning is not an exact science and the weather is the single most influential factor in determining how many days from pruning cut to opening bud. The severity of pruning (how much of the cane is removed) also affects the time to maturity as apical dominance of the primary bud at the cut comes into play. Anyway, enjoy your roses and begin pruning by mid-August to produce a bevy of lovely blooms by early October whether you plan to show them or just for sharing and arrangements.
Hope you have an eventful summer. Pamper your roses... they'll return the favor this fall.