How to Make Herb Topiaries & How to Trim the Top

Choosing Herbs

• The best herbs to use for topiaries are those with sturdy stems that will easily wind around a frame. Lemon thyme (Thymus x citriodorus), sage (Salvia officinalis), and oregano (Origanum vulgare) are all shrubby perennials that are hardy in U.S. Department of Agriculture plant hardiness zones 5 to 8. Rosemary (Rosmarinus officinalis ) is another great choice, and is hardy in zones 8 to 10. They all enjoy full sun, moderate moisture and well drained soil. If they are healthy, most herbs have dense enough foliage to cover the frame completely, so choose your herbs based on personal preference and the specific growing conditions in which it will live.

Planting Pointers

• Plant the herbs in pots proportionate in size to the wire frame you are going to use to create your topiary design. For example, a 10-inch-high frame will require a pot at least 6 inches in diameter to accommodate the size the plant will grow to when the topiary is mature. Remember that some designs, especially the lollipop or double globe, will be rather top heavy when mature, so ensure your pot is heavy enough to avoid easily tipping over. The pot should also have a drainage hole. Use a good quality potting soil mix and add a bit of granular fertilizer to the mix before you add your plants. For a 6-inch inch pot, 1/4 cup of fertilizer is adequate. This will help reduce the shock to the plant that comes with transplanting, and it will get new growth started as soon as possible.

Adding the Frame

• Insert the wire uprights of the topiary frame into the middle of the plant, pressing the wire down deep enough, one to several inches, so that the frame is supported well. Don't worry about hurting the plant with the wire frame -- the root damage will be minimal and the plant will quickly repair itself. Gently winding the stems of the herb around the frame, starting from the very bottom. Most likely, you will not be able to cover the frame completely with the stems of the plant. That will come in time. If necessary, loosely tie the woody stems of the plant to the frame until it begins to establish itself. Be careful not to tie too tightly, which can damage the plant. Some herbs, like thyme, have more of a vining habit and will begin to wind around the frame without too much encouragement after a month or two of training. Others, such as rosemary, will continuously need to have new growth trained on the frame.

Trimming Tips

• As your topiary grows, continue to train the new growth around the frame. Once the frame is completely covered by the plant, trim just enough, using sharp kitchen shears or small garden clippers, to keep it neat and shapely. Trim foliage that is sticking up or out of the top or sides of the frame, 1/2 inch at a time, following the shape of the frame closely. Before trimming, clean the clippers with a cotton ball dipped in peroxide between uses to avoid cross contamination. Fertilize monthly throughout the growing season, using a 30-30-30 all-purpose liquid fertilizer. Mix approximately 1 tablespoon of fertilizer with 1 quart of water, following package directions. Water the soil with the mixture carefully so that it doesn't splash on foliage. If your herbs are not winter-hardy where you live, bring indoors before the first frost, and set in a spot that receives direct sun for at least half the day.