Roses are among the most beautiful of all garden plants, but they take up a lot of space in the garden. One option is to grow them in containers, which lets you take advantage of the space on a deck or patio, or even on stairways. Planting in pots also offers you more control of moisture levels and exposure to sunlight. Finally, growing potted roses is a good option if your local garden soil is poor and ill-suited for growing good roses.
Tools and Supplies You Will Need
- Large pots or planting containers
- Commercial potting soil
- Garden compost
- Composted manure
- Bonemeal or blood meal
- Rose plants
- Rose fertilizer
- Epsom salts
Pick the Right Roses
Not all roses will work well when planted in pots. For example, unless you put it against a trellis or provide some other type of support, a climbing rose is a poor choice, as it will sprawl out everywhere. Likewise, grandiflora roses tend to be on the taller side and have large blooms, and they can be prone to tipping or blowing over when planted in containers. Shrub roses, species roses, and older rose cultivars reach dimensions that make it difficult to grow in a contained space as well. It's also best to leave the hybrid tea roses to your garden, as they do not usually grow well in pots.
However, there are four types of roses that are especially suitable for containers:
- Ground cover: These stay low and look lovely when they spill over the edges of a container. Depending on the size of your pot and the variety of ground-cover rose, it may also be possible to use it as a border around a larger plant.
- Miniature: These types of roses have been cultivated to stay on the small side, so they are naturally well suited to growing in containers.
- Patio: If you want a rose that is larger than a miniature but not as big as a standard rose, try a patio rose. This is a type of floribunda, bred to a smaller scale.
- Polyantha: This type bears clusters of small roses on a shorter plant. Check the tag to make sure you are not purchasing a climbing type of polyantha.
Prepare the Containers and Potting Soil
There is a delicate balance to be maintained when you are planting roses (or any other plant) in containers. Use a potting medium that drains well enough to diminish the likelihood of root rot while being heavy enough to hold moisture. A planting medium that drains too fast will dry out before the roots can take up moisture, and soil that is too heavy in organic material can become soggy, fostering rot.
Choose a relatively large, tall pot when growing a rose bush. Many experts recommend a pot no less than 15 inches in diameter. Roses send down deep roots, so the taller the container, the better. The soil in pots heats up faster than garden soil, so clay pots are generally better than plastic since clay is slower to transfer heat from the sun into the soil. If you must use plastic pots, use lighter colored plastic, which won't heat up as fast as dark plastic. Make sure the pots have ample drainage holes in the bottom. Place a layer of gravel or medium-sized rock about 1 inch deep in the bottom of the container.
Create a potting soil mixture consisting of one-third quality commercial potting soil, one-third garden compost, and one-third composted manure. Add a cup of perlite to enhance drainage. Add 1 cup of bonemeal to the soil mixture. If you wish, you can also add fishmeal or blood meal for added nutrients.
Fill the pot about two-thirds full of prepared soil mix. If planting a bare root rose, mound the soil up in the center, then place the rose over the mound and spread the roots out over it. If planting a potted rose, just create a slight indentation, then remove the rose from its nursery container and place it into the pot. Fill in around the rose using the remaining potting soil, pressing it down firmly around the lower canes. The soil surface should be level with the bud union—the point where the rose is grafted to the rootstock. Fill the container right to the top with soil; it will settle with time.
Place your potted roses in a location that gets at least seven hours of direct sun each day. On patios and decks, this may mean moving the pots around over the course of the day to keep them in the sun. If you are growing groups of potted roses, keep them spaced at least 2 feet apart to ensure good air circulation.
Immediately after planting, water the plant thoroughly so that all the soil is well saturated. Keep an eye on your roses so you know when to water. A good general rule of thumb is to water when the top of the soil surface is dry. Keep potted roses in soil that is moist, not wet—ideally, the soil should have the dampness of a wrung-out sponge.
- You will have more success if you do not water between 10 a.m. and 6 p.m. This is typically the hottest part of the day, and evaporation is accelerated during this time.
- As much as possible, try to keep water off the leaves. Wet leaves can lead to powdery mildew and other fungi and plant diseases.
- Drip irrigation can be a great way to keep your container roses happy. These systems are designed to deliver the water directly to the root zone instead of spraying the foliage.
When you place a rose within a finite amount of soil in a pot, it can quickly use up all of the nutrients available. Roses are heavy feeders in any situation, but when grown in pots they require more frequent feeding than when planted in the garden. Apply a balanced fertilizer designed for roses every other week to make sure that your plants have access to all of the food they need for proper growth and vigorous blooming. Any balanced fertilizer works fine for roses; those marketed as "rose fertilizers" may have additional ingredients aimed at preventing fungal diseases or pests. In spring, some growers spread a tablespoon of Epsom salts around the base of the plant, which provides magnesium for healthy foliage.
Follow the fertilizer directions carefully as over-fertilizing can be as bad or worse than not feeding at all. Apply fertilizer to the soil and not the leaves (unless the directions instruct you to do so) because foliage can be burned by the salts in fertilizers.
You should stop fertilizing about eights weeks before the expected first winter frost. This will prevent the plant from developing tender young shoots that will be destroyed by the frost.
Repot Every Few Years
Other than miniature roses, most roses grown in pots need to be repotted every two or three years, since they are heavy feeders that quickly exhaust potting soils. Using freshly prepared potting soil each time you repot will keep the nutrient levels at an acceptable level. Over time, salts and minerals from fertilizers can also accumulate in the soil. This can potentially damage the rose, but changing the soil regularly should prevent that. Exhausted potting soil can be added to the compost bin.
Protect From Freezing Temperature
Every fall, gardeners in cooler zones need a strategy for protecting their container roses from the ravages of winter. Plants in pots get much colder than those in the ground, so this is a very important step. For roses to survive the winter in pots, they should be rated at least two USDA hardiness zones colder than the one you live in. For example, if you are in zone 6, grow potted roses rated for zone 4.
To protect your potted rose, you have several options:
- Mulch the base: If the winter weather is just a little chillier than your plant is rated for, you can add some mulch to the top of the container and mound it around the pot to add insulation. However, be sure to keep the mulch away from the plant itself. If wet materials are constantly touching the trunk or branches, it greatly increases the chances that insects or diseases will attack your rose.
- Bury it: If you have space, another option is to dig a hole in your landscape and place the entire container inside. Cover the soil at the top of the container with garden soil, but make sure the soil doesn't touch the crown (where the plant meets the roots). Gardeners in very cold climates sometimes build insulating structures out of chicken wire and straw or dried leaves to insulate the above-ground canes of their roses through the winter. Though this is not a very attractive technique, it can help your roses survive through the harshest winter climates.
- Build a cold frame: Even though they are unheated, structures such as a cold frame or sturdy hoop house can raise winter temperatures enough to prevent winter from damaging your potted roses. This generally works in moderately cold climates, but not in areas with the most severe winters.
- Bring it inside: If you have room, and windows that provide enough sun, your rose may enjoy spending winters inside your garage or home. As you switch locations, harden the plant off to help it gradually acclimate to the new environment.
Address Pests and Diseases
Potted roses are susceptible to many of the same pests and diseases that can plague roses planted in the garden.
The most common insect that you will find on your roses is the aphid. Aphids usually congregate on the buds and leaves where they suck out juices, making the affected parts wither. When you first spot aphids, use a hose to spray them off the plant. Do this in the morning so the rose has time to dry off before temperatures drop, which can promote fungal diseases and rot. Or, you can also pick the aphids off by hand, though this can be a tedious task if the plant is badly infested with the tiny insects.
Potted roses are susceptible to a variety of fungal diseases, including powdery mildew and black spot. While there are fungicides that can treat fungal diseases on roses, the best strategy is preventive—to makes sure the roses have good air circulation, which reduces the chances of fungal infection.