Before planting roses, it’s a good idea to check the pH and drainage of the area you are going to plant in. If you want healthy robust rose plants that bloom prolifically you’ll want to make sure these two areas are part of your pre-planting preparation. A sickly rose plant is a beacon to pests and disease. They just seem to know when a plant is doing poorly and zoom straight in for the kill! What goes on above soil level is a reflection of what’s going on beneath soil level, so it’s the smart rose gardener that takes the time to check the soil pH and drainage
If you’re starting a new rose garden, check the soil pH level first. Soil pH testing is easy. You can get a pH test kit at your local garden centre – they’re cheap and it only takes a few minutes to do the test – just follow the simple directions on the package. The pH level in soil affects the availability of soil nutrients to a plant. Your rose bush could be sitting in soil teeming with all the nutrients it needs for its optimal growth, but if the soil pH is too high or too low, some of those nutrients won’t be made available to it. The best soil pH for planting roses is between 6 and 7 and all nutrients are made available to the plant in this pH range.
The next step is to check the drainage of the area you intend planting roses in. A good way to do this is to dig a hole 30 cms (1ft) deep and fill it with water and see how long it takes to drain away. If the water is still there after several hours it’s an indication that the site has poor drainage. If plant roots are sitting in water for extended periods because it can’t drain away in a reasonable amount of time, the tiny hairs on those roots that uptake the soil water and nutrients into the plant start to rot and die, closely followed by the roots themselves.
So over a period of time the roots rot away and though the rose bush is getting plenty of water, it can’t take it up. It’s all downhill from here. The plant fails to thrive, leaves yellow and drop, it becomes susceptible to pest and disease attack because of its weakened state and slowly dies. You on the other hand, if you haven’t checked for drainage problems, have no idea that all this is occurring beneath the soil surface and can’t work out why your rose plant is not doing well, despite your best efforts of regularly watering and feeding it.
Two ways to remedy poor drainage before planting roses are either to install some drainage pipes or raise the height of the garden beds by about 20 cms (8 inches). Fill the raised beds with some good quality top soil bought from a reputable supplier, along with some compost and well rotted manures.