Fertilizer for Prostrate Juniper

Fertilization at Planting

• To plant a prostrate juniper, dig a hole as deep and about twice as wide as the root ball or pot. Place the juniper in the hole so the crown, or the place where roots meet branches, is just above soil level. Replace the soil without mixing anything into it, and then spread 2 teaspoons of 10-10-10 fertilizer around the plant and water it in.

Mature Plants

• Mature junipers will benefit from a complete fertilizer such as 16-4-8 or 12-4-8 in spring just before new growth begins and again in early summer. Spread 1/2-pound of fertilizer per 100 square feet on the soil and water it in. In cold climates, do not fertilize after midsummer. This will cause tender new growth late in the season that may freeze in the winter. The soil around the juniper can also be top dressed with aged manure or compost.

Minor Nutrients

• Chlorosis, or yellowing of the leaves, can be caused by overwatering, soil compaction or over application of certain nutrients, but the most common cause is a lack of iron or magnesium. The fastest remedy is to spray the plant with a liquid micronutrient fertilizer solution, applied according to manufacturer's directions. This can be done whenever the chlorosis appears. If high calcium levels in the soil are preventing the plants from absorbing iron, sulfur can be added to reduce the pH over a period of years.

Soil Tests

• If application of fertilizer at the recommended rates does not produce adequate growth or good color, a soil test will help determine what deficiencies are causing the problem. Good soil test kits are available at garden supply stores or online. Testing involves taking a small sample of soil, mixing it with distilled water and the test solution from the kit and comparing the resulting color to a chart that comes with the kit. Follow the directions that come with the kit for accurate results.