Soil Composition: The Root of the Matter!
by Jill Barnard
Our goal as rose growers is to have mass quantities of blooms to enjoy. Before we can expect this kind of production from the top of the bush, we must pay close attention to the bottom of the bush: the roots, and the soil in which they grow.
THE ROOT SYSTEM: The root system has two main functions. Anchor roots serve as the anchor for the plant, providing stability for the weight of the top growth and resistance to the forces of nature. Feeder roots extract air, water and nutrients from the soil that provide energy for top growth.
When you acquire a bare root rose, or even a small container rose, its roots are small, and can only sustain a few short canes until the thousand of tiny feeder roots necessary to support a larger bush are developed. This is why it is so important, albeit difficult, to cut the canes on a bare root plant back to 6 inches in length at planting time. By reducing the number of bud eyes along the shorter canes, you direct the limited amount of growth energy into fewer but stronger stems. You also allow the root system to grow before the top growth overwhelms it.
ANCHOR roots should be directed downward at planting time, where the soil is less likely to dry out in the heat of the summer. Since roots will take the path of least resistance, they can easily be directed deeper by making the soil more inviting at deeper levels. The hole you dig at planting time provides the vehicle for good root growth. The texture of the soil must be improved to a depth of 18 - 24". Deep watering your fertilizers into the soil depths will discourage the anchor roots from surfacing. Deep watering with 2 gallons per bush weekly is the method of choice during average summer months. In hot weather, add daily surface watering to keep the soil surface moist and cool.
FEEDER roots will grow out from the center of the bush to a diameter of three feet or more, depending upon the size of the top growth. The 2-foot width of the preferred planting hole is not over-kill. These delicate roots need to be able to move through a light, porous soil in search of food, air and water.
SOIL CONDITIONS: What goes on above ground level is largely dictated by what goes on below ground level. Whether the plant thrives or merely survives depends upon the conditions its roots encounter in the soil. Successful rose growers grow healthy, vigorous root systems. The root system will then grow healthy, vigorous top growth with abundant blooms. Don't compromise on the basic components of soil building: Texture, Nutrients, Water and pH.
SOIL TEXTURE
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 unfortunately the best amendments, such as compost, aged manures and redwood forest mulch, must be purchased. 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
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.
The term nutrients means not only a balance of Nitrogen, Phosphorus and Potassium (N-P-K), but also the secondary and trace elements required by roses. These include calcium, magnesium, sulphur, iron, zinc, copper, cobalt, boron and others. Some nutrients are available in soil, but most should be added to insure adequate supply for vigorous growth. These nutrients are the products we supply on a monthly basis. In order for them to work properly, the soil must be in a receptive condition - light in texture with good moisture and air supply.
When you add an organic fertilizer to the soil, it must be broken down into a form that is readily available to the rose plant. Soil micro-organisms do this for us, providing a slow release of nutrients to the plant. Chemical fertilizers are man-made, and are generally a quicker (more soluble) source of food - usable almost instantly by the plant. Roses benefit from both sources, and both should be used on an alternating basis.
Regardless of the source, nutrients are taken up by the roots from the soil. Most of the essential nutrients are translocated within the plant tissue: that is, they are moved within the upper growth rather easily from an area in which they are no longer critical, to an area of new growth. This is particularly true of nitrogen, phosphorus, potassium and magnesium. Therefore, the signs of deficiency of these materials occur on old foliage at the base of the bush first. In contrast, iron is not translocated, and if deficient, the new foliage becomes yellow first.
If we feed roses once a month with a balanced food there should be no shortage of N-P-K. High calcium content of soil can render magnesium useless, so addition of epsom salts (magnesium sulphate) two or three times a year is a wise practice. There is usually enough iron in our soil, but this element more than any other is available to the roots only if the soil has the correct acidity. Addition of a chelated form of iron every six weeks will ensure healthy, green foliage. What do we mean by acidity? We mean the pH of your soil - the last, but not the least important consideration in soil building.
ALL IMPORTANT SOIL pH
Without becoming technical, “pH” is the measure of soil acidity or alkalinity. pH is measured on a scale of 0 to 14, with 7.0 being neutral. Acid soils register below 7.0, alkaline soils above 7.0. The soil pH has a direct effect on the ability of plant root cells to absorb both nutrients and water from the soil.
For roses, the ideal pH is between 6.4 and 7.0, or slightly acidic. Below 6.5, phosphorus begins to become unusable by plant roots. At 6.0 it is almost totally lost to the plant. Nitrogen, potassium, calcium and magnesium will decline in their effectiveness below 6.0. but not to the same extreme.
Above 6.5, iron and manganese begin to become locked up and unavailable; above 7.0 boron, copper and zinc begin their decline. It is clear then, that 6.4 - 7.0 is the range in which roses can utilize the greatest degree of all nutrients combined.
Soils west of the Mississippi tend to be alkaline and require annual additions of soil sulphur to lower the pH. Eastern soils are more acidic and require addition of lime to raise the pH. Check with your county extension to determine the conditions in your area, and apply the necessary products once or twice a year according to their instruction. They can also advise you how to have your soil tested for total content - pH, nutrients, organic content and other conditions.
Understanding and utilizing the knowledge of what a rose requires for vigorous, healthy growth below the soil surface will reward you with a higher appreciation of the results you witness above the ground. Soil building is not just important, it is the root of the matter.
When you acquire a bare root rose, or even a small container rose, its roots are small, and can only sustain a few short canes until the thousand of tiny feeder roots necessary to support a larger bush are developed. This is why it is so important, albeit difficult, to cut the canes on a bare root plant back to 6 inches in length at planting time. By reducing the number of bud eyes along the shorter canes, you direct the limited amount of growth energy into fewer but stronger stems. You also allow the root system to grow before the top growth overwhelms it.
ANCHOR roots should be directed downward at planting time, where the soil is less likely to dry out in the heat of the summer. Since roots will take the path of least resistance, they can easily be directed deeper by making the soil more inviting at deeper levels. The hole you dig at planting time provides the vehicle for good root growth. The texture of the soil must be improved to a depth of 18 - 24". Deep watering your fertilizers into the soil depths will discourage the anchor roots from surfacing. Deep watering with 2 gallons per bush weekly is the method of choice during average summer months. In hot weather, add daily surface watering to keep the soil surface moist and cool.
FEEDER roots will grow out from the center of the bush to a diameter of three feet or more, depending upon the size of the top growth. The 2-foot width of the preferred planting hole is not over-kill. These delicate roots need to be able to move through a light, porous soil in search of food, air and water.
SOIL CONDITIONS: What goes on above ground level is largely dictated by what goes on below ground level. Whether the plant thrives or merely survives depends upon the conditions its roots encounter in the soil. Successful rose growers grow healthy, vigorous root systems. The root system will then grow healthy, vigorous top growth with abundant blooms. Don't compromise on the basic components of soil building: Texture, Nutrients, Water and pH.
SOIL TEXTURE
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 unfortunately the best amendments, such as compost, aged manures and redwood forest mulch, must be purchased. 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
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.
The term nutrients means not only a balance of Nitrogen, Phosphorus and Potassium (N-P-K), but also the secondary and trace elements required by roses. These include calcium, magnesium, sulphur, iron, zinc, copper, cobalt, boron and others. Some nutrients are available in soil, but most should be added to insure adequate supply for vigorous growth. These nutrients are the products we supply on a monthly basis. In order for them to work properly, the soil must be in a receptive condition - light in texture with good moisture and air supply.
When you add an organic fertilizer to the soil, it must be broken down into a form that is readily available to the rose plant. Soil micro-organisms do this for us, providing a slow release of nutrients to the plant. Chemical fertilizers are man-made, and are generally a quicker (more soluble) source of food - usable almost instantly by the plant. Roses benefit from both sources, and both should be used on an alternating basis.
Regardless of the source, nutrients are taken up by the roots from the soil. Most of the essential nutrients are translocated within the plant tissue: that is, they are moved within the upper growth rather easily from an area in which they are no longer critical, to an area of new growth. This is particularly true of nitrogen, phosphorus, potassium and magnesium. Therefore, the signs of deficiency of these materials occur on old foliage at the base of the bush first. In contrast, iron is not translocated, and if deficient, the new foliage becomes yellow first.
If we feed roses once a month with a balanced food there should be no shortage of N-P-K. High calcium content of soil can render magnesium useless, so addition of epsom salts (magnesium sulphate) two or three times a year is a wise practice. There is usually enough iron in our soil, but this element more than any other is available to the roots only if the soil has the correct acidity. Addition of a chelated form of iron every six weeks will ensure healthy, green foliage. What do we mean by acidity? We mean the pH of your soil - the last, but not the least important consideration in soil building.
ALL IMPORTANT SOIL pH
Without becoming technical, “pH” is the measure of soil acidity or alkalinity. pH is measured on a scale of 0 to 14, with 7.0 being neutral. Acid soils register below 7.0, alkaline soils above 7.0. The soil pH has a direct effect on the ability of plant root cells to absorb both nutrients and water from the soil.
For roses, the ideal pH is between 6.4 and 7.0, or slightly acidic. Below 6.5, phosphorus begins to become unusable by plant roots. At 6.0 it is almost totally lost to the plant. Nitrogen, potassium, calcium and magnesium will decline in their effectiveness below 6.0. but not to the same extreme.
Above 6.5, iron and manganese begin to become locked up and unavailable; above 7.0 boron, copper and zinc begin their decline. It is clear then, that 6.4 - 7.0 is the range in which roses can utilize the greatest degree of all nutrients combined.
Soils west of the Mississippi tend to be alkaline and require annual additions of soil sulphur to lower the pH. Eastern soils are more acidic and require addition of lime to raise the pH. Check with your county extension to determine the conditions in your area, and apply the necessary products once or twice a year according to their instruction. They can also advise you how to have your soil tested for total content - pH, nutrients, organic content and other conditions.
Understanding and utilizing the knowledge of what a rose requires for vigorous, healthy growth below the soil surface will reward you with a higher appreciation of the results you witness above the ground. Soil building is not just important, it is the root of the matter.
