Gardening Today: Roses
The rose has been referred to as the 'queen of flowers' for over 2,500 years, since long before they reached their present point of refinement. Today's roses have inherited more from their revered ancestors than the concrete characteristics of basic flower form and leaf shape. As the worldwide love of roses attests, they are also heirs to a special regard stretching far back in time. The 'modern' era of rose growing began in 1867, with the introduction of what is now designated the first of the hybrid tea roses-the class that dominates present-day gardens.
Hybrid Tea Rose
Of all the different types of roses, hybrid tea roses are the most popular. The plants are tall and stately with large, well-formed blooms on long stems that are suitable for cutting.
Floribundas are shorter growing roses which were bred for landscaping use. Although the blooms on floribundas are smaller than hybrid tea roses, they are produced in abundant clusters from June until frost. Floribundas will also make fine hedges, planted fairly close in two staggered rows.
These roses are crosses between hybrid teas and floribundas. They have medium to large flowers which are produced in clusters on tall-growing plants.
This type of rose produces long canes which require some support to hold the plants up off the ground. Climbing roses, like bush roses, are grouped in several types: ramblers, everblooming climbers, climbing hybrid teas, climbing polyanthas, climbing floribundas and trailing roses.
Flowers of polyantha roses are borne in large clusters. They tend to flower only once a year in early summer. Their chief use is in massed landscape plantings.
For many years, roses that fit no other category were called 'shrub roses'. This category now defines a large group of wild and hybrid roses which develop vigorous, dense growth. They are all very winter-hardy with minimal winter-kill of canes. The flowers may be single or double, small or large.
The plant sizes range from foot-tall ground covers to eight foot tall shrubs. Shrub roses are most effectively used as flowering shrubs massed together in the landscape or as hedges. 'David Austin English Roses' have recently been added to the shrub rose class. These roses have been bred by crossing spring-flowering old garden roses with contemporary floribundas and hybrid tea roses, resulting in old-fashioned type roses which are repeat bloomers.
This group includes varieties and species that were grown in Colonial times. Although the flowers are not as attractive as those of the new varieties, they are usually much more fragrant. Old-fashioned roses bloom heavily in June, are very hardy, and require little care. If interested in old-fashioned roses check the "David Austin English Rose" selections.
Tree roses are not a natural rose form. They are made by grafting wood from a floribunda or hybrid tea rose onto a tall, straight cane.
These little bushes grow less than 2 feet tall, and produce perfectly formed, tiny blooms. Their tiny habit makes them ideal for mixing with perennial flowers and for growing in containers or window boxes.
Hybrid Tea Roses can be spaced 24-30 inches apart in Montana. Floribundas can be spaced 18-24 inches apart.
Plant your roses where they receive at least 4 to 6 hours of sun daily. The more sun the better. Locations that receive early morning sun offer better protection against mildew. Morning sun will evaporate moisture on the foliage which often leads to the development of several leaf diseases.
Any good garden soil will produce good roses. But since our soils are usually lacking in organic matter, it is a good idea to work peat moss or compost into the soil to a depth of about 2 feet. Add about 1 part organic matter to every 3 parts soil.
Remove the plant carefully from its container, keeping the root ball intact. Position the root ball in the hole so that the 'bud-union' is situated about 2 inches below the surrounding soil level. The 'bud-union' is a bump or knob on the lowest part of the stem where the plant has been grafted to a hardier, more vigorous rootstock. Roses that have no 'bud-union' should be planted so that the juncture of the roots and stems is just below the surrounding soil level. Fill in soil around the plant until half-full, water it in, and fill in the remaining soil and water again. Mound soil around the plant in a ring. Build a water reservoir around the plant by mounding soil in a 2 foot diameter circle around the base of the plant.
Roses should receive the equivalent of 1 inch of water every 7 to 10 days throughout the growing season. Soak the soil thoroughly to a depth of 8 to 10 inches. Don't forget to continue watering your roses even when they are dormant if the soil is very dry but not frozen.
Cultivating and Mulching
Cultivate roses carefully; their roots may grow close to the surface and be injured by deep cultivation. Since the main reason for cultivation is to remove weeds, a good substitute for hand-weeding is the use of a landscape fabric around the base of the plants covered by a mulch. The fabric and mulch will help conserve moisture and keep the root zone cooler.
Roses grow best in soil that is medium to slightly acid. The best way to increase the acidity of our generally alkaline soil, is to add sulfur. Our soil, because of its alkalinity, also makes iron unavailable to the plant. We recommend Bill's Rose Food which is a complete fertilizer (containing nitrogen, phosphorous, and potassium) and the beneficial addition of sulfur and iron. Spread the fertilizer evenly around each plant at the drip line, being careful not apply any fertilizer next to the base of the plant. Apply fertilizer when new spring growth is well established and all danger of frost is past. A second application can be made later in the season. Do not apply fertilizer after July 15. Application of fertilizer after this time could stimulate fresh growth and delay hardening of the wood before winter sets in.
Prune in early spring, just before rowth starts. First remove the dead wood being careful to cut an inch or so below the dark-colored dead wood. Next cut out all weak growth and any canes or branches growing toward the center of the bush. Remove any crossing branches. Finally, shape the plant by cutting the strong canes to a uniform height.
Prune only to thin out and remove old canes. They don't require shaping, since most shrub roses are most attractive when they are allowed to develop their natural shape.
Hybrid Tea Roses
Soon after the first killing frost, mound soil 8 to 10 inches high around the base of the canes. The mound of soil will help keep the soil temperature more constant. Often it is not low winter temperatures that kill roses, but the fluctuation of temperatures, common in Montana, that do more harm. The plant is often tricked into breaking dormancy during a warm spell and this tender growth can be killed by the next cold spell. Remove the soil mound in spring as soon as danger of severe frost has passed.
Tree roses need special winter protection because their grafted top is so susceptible to winter's freezing temperatures. The entire plant will have to be laid in a trench next to the plant and covered with a protective, insulating layer of soil. Begin by digging a suitable long trench next to the tree rose. Then dig carefully under the roots on one side of the plant until it can be pulled over into the trench without breaking all the root connections with the soil. cover the entire plant with at least 10 inches of soil. In spring, after the danger of frost is past, dig up the tree rose and set upright again.
Lay the canes on the ground or in a shallow trench dug next to the plant, hold them down with wire pins and cover them with several inches of soil.
Roses in Containers
In order to survive the winter in Montana, roses grown in containers will have to be buried in insulating soil, with or without the pot. Remove the plant from the container or sink the entire pot into a deep hole in the garden, deep enough to cover the root area and at least a foot of the bottom of the canes. You can further insulate the plant by mounding soil around the canes still further.
These usually appear in early spring on new growth. They are soft-bodied, 1/8 inch long insects that may be green, red or black. Their presence can slow growth, or stunt or deform leaves.
Control: Blast infestations with a strong stream of water. Spray with a repellant soap solution. Spray with Malathion or Isotox.
Worms which bore into new shoots and eat the inside of the stem, causing wilting of the new growth tips.
Caterpillars will skeletonize leaves or chew holes in them.
Control: Spray with Bacillus, Thuringiensis, or contact insecticides such as a Diazinon, Sevin, or systemic insecticide such as Isotox.
They damage the plant by sucking juices from leaves, causing them to look yellow-gray and dry. Undersides of leaves often show silvery webbing.
Control: Spray with a contact miticide, such as Isotox or an insecticidal soap.
Found in flower buds, sucking juices in unopened petals. These are near-invisiable insects that deform and discolor flower petals.
Control: Best treated with a systemic insecticide such as Isotox.
A fungus disease that causes black spots on the leaves. Tissue around the spots turns yellow.
Control: Treat with a systemic fungicide, such as Benomyl or Daconil.
Creates a white, furry, powdery coating on leaves, stems, and flower buds. Infected leaves become distorted.
Control: Increase aeration around the plant. Water only in the morning. Spray with systemic fungicide such as Benomyl or Daconil.
Produce small orange spots on the undersides of leaves. Yellow blotches appear on leaf surfaces.
Control: Treat with a systemic fungicide such as Funginex or Daconil.