Answer: Most roses grow well with a soil pH of 5.5 to 7. There in Florida most soils are slightly acidic (acidity usually occurs in areas with high rainfall; alkalinity occurs in areas with low rainfall). There are exceptions, of course, but I suspect your soil is in the 5.5 to 6.0 range. You shouldn't have to adjust it to grow roses.
If, after planting your roses you notice some nutrient deficiencies even though you fertilize regularly, it would indicate the soil is too acidic or too alkaline and is therefore binding up the nutrients instead of making them available to the plant's roots. In this case you can adjust the elements to provide just what your roses need. Here's a short list of symptoms you might encounter if your soil pH is on the very low or very high side:
Chlorosis or Iron Deficiency
The new leaves and shoots on your roses appear as light yellow green to white with darker green veins showing. This is the most common and apparent deficiency to occur in roses. Photosynthesis needs iron in order to work. If there is no iron there is no chlorophyll, hence the rose leaves cannot turn green. This is most commonly caused by clay soils. Certain kinds of clay (clays are a group of several different minerals) 'eat' iron as they go about the process of chemical weathering.
Treatment: This condition necessitates the addition of chelated iron to the soil on a regular basis. Just a handful around the base of the plant out to about 1 foot in radius is enough to start fix the problem usually. There are some iron additives that include nitrogen fertilizers with them, so that you can kill two birds with one stone.
Leaves are pale and yellow in the center with dead areas close to the middle of the leaf. Oldest leaves are the first affected. Leaves fall off the plant early.
Treatment: Add a fertilizer containing Magnesium.
Young leaves appear to be small and pale green. Veins are a lighter yellow color. Rusty red spots sometimes develop in the center of the leaves. Stems appear small and short. The overall rose becomes stunted or even defoliated. This is caused by the rose using up all of the available nitrogen in the soil, or by the breakdown of too much wood or bark mulch or fall leaves. Balancing your mulch with grass clippings can help you with this situation.
Treatment: Add fertilizer. But not just a 'Nitrogen only' lawn fertilizer, use a well balanced fertilizer with an NPK ratio of about 1:2:1. Roses short in Nitrogen are most likely to also be short in other nutrients as well.
Mature leaves stay green, but develop brown dead brittle edges. Young new leaves are red and don't turn green. Flowers develop but they appear small. Potassium is the nutrient that is the K of 'NPK' fertilizers. It is the third number on the list of say a label that reads: 10:20:10 for example. K is the chemical symbol for the element Potassium. Potassium shortage is a condition that is common in soils that are sandy.
Treatment: Apply a compound fertilizer that contains potassium or 'K'.
Young leaves grow small and are very dark green. Purplish tints on the underside of the leaves near the center. The leaves fall off of the plant early. The plant will not bloom. Stems are weak and small. The bush appears stunted and will not get bigger.
Treatment: Apply a compound (NPK) fertilizer. Make sure that it is high in P (Phosphates).
The oldest leaves on the plant will get yellowish bands between the veins. While the veins remain green. This condition usually occurs when people are trying to raise the pH of their soil and add too much lime to the soil. Thus over doing it.
Treatment: Avoid over liming. If the symptoms persist there are manganese additives available at most garden centers.
I realize this is a long answer to a short question but I wanted you to have an overall view! Best wishes with your roses.
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