Hybrid tea roses need not go half dormant during July and August. They are benefited by being kept in full growth. They are more attractive, too, because they can and do bloom during this period.
Under the old system, the plants were pruned rather severely right after the June bloom, and any buds which formed were removed “to throw the strength into the plant.”
At the same time, water and fertilizer were withheld, preventing much growth and building of strength.
The heat and some degree of drought forced plants into semi-dormancy. Leaves, the factories of food and strength, dropped from the plants, and the rose garden was a place to avoid if you wanted to impress friends.
Few roses are really “ever-blooming” during the entire season from late May to November (or hard frost).
Most varieties are “croppers,” bearing one burst of bloom, producing new growth on which another burst will appear. The time lapse between successive crops varies with variety, weather, and culture.
Free-flowering Kinds
Some varieties are, however, almost constantly in bloom. Nearly Wild, a hybrid tea with small pink, single flowers, may continuously bloom from late May until frost.
Almost as faithful are the vigorous and lovely floribundas, Betty Prior and The Fairy. Among the new grandifloras, Carrousel and Queen Elizabeth have short intervals between crops.
Remember, too, that some varieties do best in cool weather and sulk in periods of heat. This is apt to be true of the wide, many-petaled varieties we imported from Europe.
On the other hand, Chrysler Imperial and Charlotte Armstrong show little effect of heat and continue to produce new crops of flowers with heartening regularity and speed. Within their limitations, here is a program that will keep roses growing steadily.
Continuous Feeding Process
A continuous feeding process should be carried out so that there will not be any limitations to healthy, vigorous growth.
In the usual “commercial fertilizers,” there are many good “rose foods” and good standard analyses like 5-8-7, 5-10-5, and 4-12-4.
The latter is somewhat low in nitrogen, and if you use it, supplement the feeding with ammonium sulfate, urea, or some other nitrogen source.
I like a 10—6-4 mixture for the first spring feeding. After that, applications of these fertilizers should be made every four to six weeks up until about seven or eight weeks before you expect hard frost.
The usual dosage of about two tablespoonsful per plant every four to six weeks may safely be increased if the plants are large and a great amount of water is used.
Be careful not to work this fertilizer deeply into the soil, as you will injure delicate feeding roots near the soil surface. Always water it well.
Generally speaking, fertilizers applied until about July 15 in the northeast can well be reasonably high in nitrogen about the amount of phosphorus and potash they contain.
After that time, however, it is wise to reduce or eliminate nitrogen to slow vegetative growth in the fall. With such a feeding practice, the plants become dormant before severely cold weather, reducing winterkill.
In addition to this feeding with a rather slow-acting fertilizer, you can use a soluble, foliar fertilizer to advantage.
In this case, a highly concentrated and soluble mixture of materials is dissolved in water and sprayed directly on the leaves of the plants. The response is surprisingly rapid.
Applying Supplementary Sprays
Normally, supplementary sprays are applied about every two or three weeks, combined with pesticides or alone. Good formulas are many.
Two of my favorite analyses are 23-21-17 and 20-2020. Burning is not dangerous when these soluble fertilizers are applied according to the manufacturer’s directions.
In the past, many forms of nitrogen had to be applied in frequent small doses if the supply of this easily translocated material was not to be a feast-or-famine proposition.
Chemists have now developed specially compounded combinations of urea and formaldehyde containing 38% nitrogen.
The characteristics of these materials are amazing. The danger of burning has been eliminated. The nitrogen cannot be leached entirely, even from sandy soils with the first heavy rain, as it becomes available over weeks at an almost constant rate.
Although some claim that enough nitrogen can be applied safely in one spring application to last the whole season, it is probably better to have several applications.
Your roses can utilize an amazing amount of water, between 1” and 2” inches, every week during active growth and flowering.
An inch or slightly more should be enough in heavier soils, but 2” inches is better where drainage is brisk. Apply in large volume and low pressure about once a week, and never use numerous sprinklings.
Watering And Mulching
Many growers build a “saucer rim” of soil around each plant as wide as the spread of the branches and fill this at each watering.
When possible, apply fairly early in the day and under no circumstances wet the foliage if the leaves stay wet for six hours or more. That is asking for an epidemic of blackspot.
No matter how much water and fertility in the soil, the roses will not benefit if the roots are inactive. When soil temperatures are high, roots almost cease to function.
Naturally, growth practically stops. One of the best ways to keep soil temperatures down in the “growing range” is to use mulch.
3” inches of ground corn cobs, 2” inches of peat moss, buckwheat hulls, grass clippings, or a small fraction of an inch of aluminum foil will be effective. At the same time, weeds are controlled, and moisture will be retained.
Pest and Disease Control
You cannot expect a rose to keep blooming and retain fully efficient clothing of leaves if the plant is pestered with insects and diseases.
Buy or mix a good all-purpose spray or dust, start your program early, and apply each week or after each rain. If mid-summer is more than usually hot and dry, spray once in 10 or 12 days.
Rose Cuttings
Avoid taking long stems when cutting blooms in June, for you rob the plants of the leaves, which should produce a later bloom.
Always allow an absolute minimum of two leaves (each having five leaflets) on the remaining portion of the stem. Cut most stems higher than this, but never cut above three-leaflet leaves.
44659 by Fred J. Nisbet