As the bare root season is fast approaching now is the perfect time to prepare your ground for planting. We suggest doing this at least a month before your bare root roses arrive, although at short notice, the use of Rootgrow products such as mycorrhizal fungi may be used on the actual day of planting.
First remove any weeds at least 50cm around intended hole and work the soil by double digging. To do this, temporily remove the first layer of soil (depth of a spade head). Then fork over the bottom layer, mixing in some fertilisers or organic material to improve root growth. For roses, phosphorus rich feeds such as bonemeal would be ideal. If you have chalky soil, its important to add a good amount of organic matter such as leaf mold, composted pine needles or well-rotted manure to balance out the PH. Backfill the top layer over to finish.
If the final destination for your rose is a pot then size does matter. Roses like to have deep roots so the taller the pot the better. A minimum depth of 40-45cm by 40cm wide is needed for shrub roses. We would not advise planting very rampant climbers or ramblers in pots, but a 1m x 1meter sized container would be needed for climbing varieties that grow below 10 feet tall. The use of a soil based compost is essential to help hold onto nutrients, so multipurpose compost on its own will not be enough. A mix of 50 percent John Innes No.3 and 50 percent multipurpose will help them thrive. A 2cm layer of gravel or crocks in the bottom can also aid drainage.
Remember the longer the roses have to develop their roots during their dormant months, the better chance of them performing at their best next summer. We hope you have a happy bare root season.
For further reference:
Planting and Pruning Guide
Root Care Products Page includes fertilisers for planting.