Monday, June 11, 2007

Planting Roses

The Gardening Trivia Quiz Last week I asked for the technical term for the "thorns" found on roses. The answer and explanation is below. Keeping with the rose theme, here is this week’s question: Roses are part of a much bigger family. What other fruiting shrubs are related to roses?

Planting Roses
One way to ensure at least one growing season, is to plant the rose properly. This means selecting the proper site, with full sun and good drainage. Full sun means 7-8 hours of sun, although it doesn’t have to be all at one time and in this case, more is better. To check for drainage, dig a hole 18" deep and fill it with water. If the hole drains within 5-6 hours, you have adequate drainage. If not, consider raising the soil level by using top soil or building a raised bed. Roses also prefer a neutral to slightly acidic soil. Having slightly acidic soil allows the plant to take up nutrients more efficiently. We ask a lot of our roses (all those magnificent blooms) and to perform roses need a soil that is light, porous, moisture holding and full of nutrients. To achieve this, most soils, especially ours here in No. Illinois, need to be amended. A 50-50 blend of native soil and some type of organic compost is best. There are many products available commercially. Composted cow manure, mushroom compost, or Cotton Burr compost are recommended.

If you are planting a large bed, you can dig the compost in the whole bed. Otherwise, when you back fill the planting hole, use a 50-50 mix of native soil and compost. When digging the hole, dig it at least 2 feet in diameter and slightly deeper that the container you purchased the rose in. It does not hurt to plant the rose graft an inch or two below the soil surface. This helps protect the bud union during our winters. It is extremely important that you dig the hole at least 2 feet in diameter so that the feeder roots, the ones responsible for taking up water and nutrients, can get established. Adding bone meal or super phosphate at the root level when planting will also help these feeder roots develop. We also recommend using a root stimulator, such as Plant Start or Quick Start, when planting. These are low in nitrogen and high in phosphorus, to encourage root growth over top growth. Once the plant is established (6 weeks or so), you can switch to a regular fertilizer.

Summer Care for Roses
Assuming you have established plants, the most important thing you can do for your roses is water and fertilize. Use a good rose or all purpose perennial fertilizer. I usually recommend using a granular, slow release fertilizer, so that nutrients are being leached into the soil continuously. If you use a water soluble fertilizer, such as Miracle-Gro, you will have to fertilize every time you water, or at least once a week. I’m not that motivated. Spread the fertilizer in a 2-3 foot diameter circle around the plant and work into the top several inches of soil, then water thoroughly. Fertilize once a month until August 1. Fertilizing after that time will cause weak canes to develop that will not survive the winter. Also this is a good time to quit deadheading. Deadheading also encourages new growth which leads to weakened canes.

Most plants need an inch of water a week. They prefer to be watered deeply to encourage the roots to grow deep rather than frequent, shallow waterings. It is best to water in the morning, and to water the soil rather than spray the foliage.

Deadheading In order to keep roses blooming it is important to remove the spent blooms, called deadheading. For the first deadheading of the season, you can cut back to 1/4 inch above the first set of 3 leaves. After that you can deadhead back to the first 5 leaf set.

Rose Diseases and Pests

Roses are susceptible to fungal infestations and several insects. Powdery mildew and blackspot are two of the most common fungi. Fungi are usually present in the soil and are best dealt with before you see them on your plants. Use a good systemic such as the Bonide Rose 3 in 1 that is a fungicide, miticide and insecticide. It is sprayed on the leaves on a regular basis. If you find powdery mildew or black spot on your rose leaves, remove the leaves and throw in the trash and begin a spray program. Make sure you water properly as this will help reduce the incidence of fungal infestations.

Roses are also susceptible to aphids and Japanese beetles. The aphids will be killed if you use the Rose 3 in 1. If you want an organice treatment, you can release ladybugs into the rose garden and they will eat the aphids. We had a customer in last week with another insect problem, the rose slug. The rose slug is actually the larvae stage of the sawfly and it can skeletonize a rose leaf very quickly.

Garden Trivia Quiz: Thorns develop from the branch tissue of a plant. The "thorns" of the rose are actually the superficial outgrowth of the stem and are correctly termed "prickles." Now, doesn't that make you feel better?

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