Hypericum St John’s Wort – Pruning, Winter Care and Fertilizing

Prune these shrubs in early spring before they leaf out. Remove 50% to 75% of the top of the shrub maintaining a mounded form. Remove the heaviest canes all the way to the ground. Some summer touch up (after the shrub blooms), to reshape and remove spent flowers, will improve the look of the plant while stimulating additional flower growth.
By fertilizing young shrubs you can increase both the size and the amount of flowers on the plant. Granular, liquid or stake type fertilizers can be used. Granular types should be worked into the soil around the plant at a rate of 2 pounds or 2 pints per 100 square feet of planting bed. This method of fertilization should only be done once a year, and is best done in late fall after leaf drop, or in early spring before bud break.

Liquid fertilizers (such as Miracle Gro) are mixed with water and applied the same as you would water the plant (see product for specific details). This should be done three or four times per year starting in late April and ending in mid July. Stake type fertilizers can be used following the directions on the package. With any of the above techniques a balanced mix should be used, 20-20-20 or 20-30-20 or 18-24-16. Organic fertilizers, like manure, can also be used with good results. The material should be worked into open soil at a rate of one bushel per one 6′ shrub or 100 sq. ft. of bed area.

These shrubs need little winter care but, should be occasionally checked for rabbit or other damage. If rabbit damage is found you can protect the plant with a fence formed with hardware cloth (looks like chicken wire but with small square holes). The branches of the plant should be tied in towards the center, then a circle of hardware cloth can be placed around the outside. The base of the hardware cloth should be buried in the soil or mulch. This protection should be installed in late November and removed in mid April.