There are times when gardeners prefer to grow roses in pots. Although they can grow well for many years in containers, there are some points that are helpful for this to be successful.
If the plants are just being kept for a short period of time while a garden is being finished or you are about to move house, roses can be placed in small 200mm pots and kept alive for several years. If on the other hand the roses are needed to be grown for a longer period of time, or permanently, a large container will be required to provide enough root area for the plant to grow within. For successful growing a half wine barrel or large plastic pot larger than 500mm diameter would be needed.
One important aspect on growing roses permanently in containers is the rose variety choice. Miniatures, floribundas, many old-world roses and smaller bush roses grow well in containers up to 500mm diameter. Larger Hybrid Tea roses, English roses, Standards and smaller climbers would require the half wine barrel size for successful growing conditions.
Now you are aware of what size container is needed, the next is what is the best soil mix to fill it with? Sometimes soil from the garden has been used to fill the pots but I do not like this, as garden soil is normally very heavy with high levels of clay in it which can expand and contract with the moisture available. When contracted the soil shrinks from the sides of the pot can cause ‘tracking’ of water down the sides of the pot with little or none entering the root-ball. Garden soil also has a high chance of weed seeds in it and will cause great annoyance when needing continual weeding.
Today we can choose from an excellent range of potting soils, which are usually composted pine-bark and sand, but do give a good medium to grow roses and other plants in. Do not be tempted to purchase the cheapest potting mix available, for cheap mix can cause many problems in establishing plant growth. Ask for Premium Mix for a quality potting bend.
Once the rose has been planted we must now plan the care of the plant. Watering is most often the main cause for a rose to die as a potted plant. Depending on daily temperatures and size of the plant, a large pot may need to be watered either daily to every three days during spring to autumn. Most pots would need daily watering when the weather is over 35 degrees, for the potting soil can become ten degrees hotter than the day temperature.
As the plants get larger the need for constant moisture increases and there are several ideas we find will keep the potting mix moist longer. Place straw mulch on top of the potting mix to keep moisture from evaporating and also keeps the roots cooler. Once a month apply a wetting agent into the watering-can such as ‘Easy Wetter’, wetter soil or any soapy product, or spread a product such as ‘Saturade‘ which will release a soapy product to soak into the potting soil. If after applying water it runs out of the pot quickly, the need for these products is vital. The reason is the potting soil has become too dry and the water is not being absorbed. By scratching your finger into the topsoil will tell if water has soaked into the root area or not.
As potting mix is just a growing medium, there is very little nutrient available for plant growth so fertilizing is vital to provide all the elements a plant needs for optimum growth. Fertilising the plant should occur every ‘growth cycle’ or every 8 weeks from October through to April or May. My preference is to use products such as ‘Sudden Impact for Roses’ which will last in the soil for many weeks after application, and provide the growing shoots with nutrients. Other products to consider are slow release fertilizers such as ‘Osmocote’.
When growing in pots the plants can become susceptible to several major pest problems. The main one to encounter and which will cause the greatest grief will be ‘Two Spotted Mite’ also known as ‘Spider Mite’. This minute mite is extremely hard to see but the damage it causes is huge. A plant with this mite infestation looks very dry, with leaves appearing grey brown to yellow, very limp, and drop off at a touch. When a leaf is placed up to the sun there appears to be webs under the leaves or looks dusty. Reason for the mites to affect the plant is caused by extreme heat over a long period, or radiating heat along a path or pavers, gravel or cement driveways, or hot walls or fences causing dry hot dusty environment. Control can be hard under these conditions as miticides are almost useless, predatory mites are expensive and only worthwhile if a huge garden is affected. So to change the hot dry dusty conditions water can be the best measure. Simply spray water up under the leaves of plants to increase the humidity and stop the breeding of this pest. Spray water thoroughly over and under the leaves in the morning for four mornings straight. By applying in the morning the plant will dry out during the day so less risk of ‘Black Spot’ another issue if higher humidity