Cool, Cool Coleus

By: Julie Barnes

What's not to love about "cool, cool" Coleus with its vibrant multi-colored foliage? In actuality, thisplant's nature is more "hot, hot" although its appearance is quite "cool, cool".

Coleus was once commonly known as painted nettle, flame nettle, or poor man's croton. It is a Mint Family (Lamiaceae) member due to its square stems and opposite leaves, but has a well-behaved growth habit that contrasts greatly with several invasive family relatives. This tender tropical perennial originates from Indonesia and Africa and is hardy only to USDA Hardiness Zone 11, so, we grow it as an annual. In the Victorian era, gardeners relied on this shade lover for dependable season long color in formal bedding schemes.

Thru a "carpet gardening" technique, Coleus was used to design flower beds into elaborate patterns. A carpet garden gave the impression of a living Persian Carpet or tapestry when viewed from a high window or balcony. Coleus is as popular now as it was then. The foliage reveals a kaleidoscope of shades or color combinations more stunning than ever before.

Growing upright, in bushy mound forms, or as trailing plants the leaves can be little, narrow, wide, round, lacy, ruffled, smooth, twisted, or in solid colors with contrasting edges. Coleus has been repeatedly crossbred over time producing an infinite number of leaf color combinations, variable plant sizes and now sun tolerant varieties. In just the last five years, the scientific name has been changed to Plectranthus scutellarioides from previously labeled Solenostemon scutellarioides, and Coleus blumei.

It performs well planted alone, grouped, combined with other coleus varieties, or mingled with flowering annuals giving bright color splashes to beds, containers or hanging baskets.

Let's now focus on this plant's needs:

Warmth- It is best to wait until night time temperatures are above 60⁰ before planting coleus outdoors. Tropical Coleus is native to areas close to the equator where there is absolutely no frost, so a mere light one can actually wipe this plant out. Also, a persistent subjecting to cool 40 -50⁰ temperatures, will adversely affect Coleus color and vigor making it more disease prone.

Sun or Shade- The new sun loving varieties can be planted in full sun. But, because coleus grows naturally in shady tropical areas, traditional varieties work best in areas with morning sun and some afternoon shade protection to bring out their best color. Too much sun can affect coloration where the plant will create more or less pigmentation to protect itself.

Watering- Coleus requires soil that is consistently moist but not wet. When exposed to sun and wind, the plant may need more frequent watering. If soil dries out completely, coleus will wilt. Watering will help the plant recover, but when allowed to dry out repeatedly, colors may become dull along with brown spots or crispy leave edges.

Fertilizing- To ensure the best color, avoid over-fertilizing Coleus. Application of a time release fertilizer is recommended but if a liquid fertilizer is used regularly, consider cutting it back to half strength.

Pinch Plants- When the coleus plant is young, pinch back the growing tips to induce branching and to create a bushier shape. Eventually Coleus will produce flower spikes. Remove them so the plants energy goes into producing beautiful leaves instead of making seeds. Finally, if you hate to bid farewell to a beloved coleus in the fall, or if you just want more plants, take cuttings. Simply cut a 4-6 inch stem, remove the bottom leaves and place the cut end into a glass of water, keeping the leaves above the waterline. Roots should sprout within days. They can be potted after a few weeks growing best in a Southern window that gets plenty of sun. They also make great houseplants.