To give the root system its ultimate environment, we must create a porous soil that holds moisture, air, and a balanced amount of nutrients to promote good root growth without damaging delicate root hairs. Soil of good texture must be made and the best amendments, such as compost, aged manures and redwood forest mulch, must be used. We call them amendments because they should not be used to the exclusion of your native soil - a 50/50 blend of native soil and amendments is good. Native soil contains important micro-organisms such as bacteria, algae, fungi and the all important earthworms. These organisms are vital to the decomposition of the amendments you will supply. Organisms abound in an organically rich soil and break it down into a form of food the plant roots can absorb easily.
The addition of organic material is perhaps the most important ingredient in good rose growing. It lightens the texture of the soil, providing a growing medium ideal for roses. Loose soil allows water to pass through the soil and across the roots, versus roots standing in water that cannot drain properly. Organic particles will retain moisture and nutrients for a continual food supply to the roots. In the process of taking up nutrients, roots also need oxygen. When you deep water, as the water level falls it pulls air down behind it. If the soil is too compacted, or has too high a clay content, the transfer of oxygen to the roots is slow and the roots cannot take up the nutrients as readily.
An organic mulch layer applied on top of the rose bed each summer will prevent hard, crusty soil that is impervious to water absorption, cool the soil for root protection and prevent weeds from gaining a stronghold.
Nutrients and water should be considered as one. Without adequate water, the presence of nutrients does no good; if you fail to feed regularly, water alone cannot sustain the health and vigor you desire in your roses.
