Coleus

Coleus scutellarioides (syn. Plectranthus scutellarioides, Solenostemon scutellarioides), commonly known as coleus, is a species of flowering plant in the family Lamiaceae and closely related to spearmint, peppermint, basil, thyme, oregano and salvia. It is native to southeast Asia through to Australia and are naturalized in many other tropical regions. It is a bushy, woody-based evergreen perennial, widely grown for the highly decorative variegated leaves found in cultivated varieties. Another common name is painted nettle, reflecting its relationship to dead nettles (Lamium species), which are in the same family.



The coleus foliage is remarkably unique, exhibiting arrays of color combinations unmatched by any other plant specie. Coleus has an aroma similar to camphor and extremely fragrant due to large amount of essential oils present in the plant. Unlike most of the mint family plants, coleus fibrous roots are used for medicinal purposes. Coleus root contains a chemical called forskolin. Herbal product manufacturers often produce coleus extracts that contain high levels of forskolin.



Table of Contents


Height(Avg)

6 - 36 inches


Width-Circumference (Avg)

6 - 36 inches


Approximate pH

6.0 - 7.0


Types of Coleus


There are hundreds of coleus cultivars available with various colors, leaf textures, and patterns. The most unique varieties include:

  • Wizard series: These are small 12- to 14-inch plants in standard color mixes. They are known to be very easy to grow from seeds.


  • Kong series: These coleus varieties have huge 6-inch leaves on big 2-foot tall plants. They are quite sensitive to direct sunlight.


  • Black Dragon: This unusual variety has deep burgundy leaves with ruffled edges. They grow to 18 inches tall.


  • Premium Sun series: These cultivars are bred to tolerate full sun.


  • Fairway series: These are dwarf coleus varieties, only 6 to 10 inches tall, in a variety of leaf patterns and colors.


  • Chocolate Mint: This has deep burgundy foliage with bright green edges, highlighting the serrated leaves. It grows to a mature height of 12 to 20 inches, with a spread of 12 to 14 inches. A bushy plant with a mounding growth habit, ‘Chocolate Mint’ thrives in full shade.


  • Watermelon: It is an eye-catching cultivar with vivid pink foliage with green margins accented with cream flecks and deep red veins. With a mature height of 20 to 22 inches tall and a spread of 18 to 22 inches, it has a mounding growth habit and provides vibrant color.


  • Kiwi Fern: This cultivar grows up to a height of 12 to 24 inches. It blooms very heavily and very quickly. The flower colors of this cultivar are baby blue and purple and it attracts hummingbirds.


There are more than 600 varieties of coleus to choose from:


Coleus for semi-shade:

  • ‘Brilliancy’ has bright red leaves with green scalloped edges.

  • ‘Fishnet Stockings’ has lime-green leaves with dark purple veins.


  • ‘Mardi Gras’ is compact and has red, green and yellow leaves.


  • ‘Japanese Giant’ has big burgundy leaves with pink and violet highlights.

Coleus for partial to full sun:

  • ‘Pineapple’ has bright lime-gold leaves with burgundy stems.

  • ‘Solar Shadow’ has green leaves with dark red serrated edges and tips.

  • ‘Alabama Sunset’ has brick-red leaves with yellow edges.



Planting Coleus


When to plant:


Start coleus seeds indoors, 8 to 12 weeks before last frost date. Transplants should only be planted long after the danger of frost has passed and soil has warmed to at least 60 degrees. Any amount of frost will damage coleus plants.


Where to plant:


The amount of light can have a dramatic impact on plant size and leaf color. For the best leaf color, a location that receives morning sun and dappled afternoon shade is best. Darker-leaved varieties tend to handle more sunlight better than those with lighter-colored leaves. Also, choose a wind-protected area, as their semi-succulent stems are prone to breakage.


How to plant:


Make sure young plants are hardened off to the light and temperature conditions of the site before planting. Amend the planting area with compost or other rich organic matter. Dig a hole slightly deeper and wider than the root ball. Tease out roots if pot bound. Place in the ground with the base of the stem at the same level it was in the pot. Backfill with soil, tamp down slightly to remove air pockets, and water well.


Coleus Care


Light


Coleus is a classic part-shade to full-shade plant, but light exposure depends on the variety. The old-fashioned seed-grown coleus does best in part shade to full shade, but newer cultivars, like the Wizard series, perform well in full sun. Too much sun can scorch leaves and cause color to fade in most classic coleus varieties. Coleus performs best with filtered morning sun and shade in the afternoon, especially in hot climates.


Plants grown in containers indoors usually get plenty of light from indirect sun during the warmer (brighter) months but may need to be exposed to filtered sunlight during the winter. It doesn't take much, but they do need some light.


Soil


Coleus prefers consistently moist, rich, well-draining soil. Before planting, amend the soil with compost or another organic material. For potted plants, any good-quality potting mix will work fine. Make sure to choose a container with drainage holes.


Container-grown coleus loves the loose texture of potting soil, and it always helps to start with a quality mix with a slightly acidic to neutral pH of 6.0 to 7.0. Provide drainage in the pot to ensure the soil isn't constantly wet, which can lead to root rot.


Water


Coleus plants grow best in soil that is consistently moist but not soggy. The soil should not remain wet all the time, but long dry spells will slow the plants’ growth, and the leaves will start to turn brown around the edges. Let the soil dry out a bit between waterings, and water when the top inch of soil feels dry to the touch. Mulch will help the soil retain moisture longer, but don't use cedar mulch, which can be toxic to coleus. Also, don't let the mulch touch the stems, as it can promote rot and hide slugs.


Coleus in containers may need watering twice a day during hot weather. Outdoor containers may require water twice a day. Indoor plants need water only when the top inch of soil feels dry to the touch.


Temperature and Humidity


As a tropical plant, coleus thrives in hot, humid conditions. In temperate climates, the barest hint of frost will spell the end of the plants. Move plants indoors or protect them on chilly nights when temperatures dip into the 50s. Make sure to take cuttings for propagation before the weather turns cold.


Keep indoor plants away from air conditioner vents and other cold spots. In dry climates, the plants will like some humidity from a humidifier or a bathroom environment. To take potted plants outdoors in spring, wait until the temperature is 70 degrees Fahrenheit or warmer.


Fertilizer


If you have rich soil, you may not need to feed coleus plants at all. If you have poor soil, add a balanced slow-release fertilizer in the bed. You’ll get the best color from your coleus leaves if you go easy on the fertilizer.


Feed container-grown plants once a month with a water-soluble fertilizer. Container plants generally need more feeding than garden plants because frequent watering washes nutrients from the potting soil.


Pruning and Propagating Coleus


Pruning


To get full, bushy plants, pinch out the growing tips when the plants are about 6 inches tall. Pinch under the flower buds if you want the plant to spend its energy on leaves and not flowers and seeds.


Plants that are not pruned tend to get leggy and lose their nice shape and dense foliage. If they remain leggy, the plants may need more sun. This is most common with indoor plants during winter so give them a bit more sun or, if necessary, artificial light.


Propagating Coleus


Favorite coleus plants can easily be propagated by taking stem cuttings and rooting them.

  1. With a sharp shearing scissor, cut a 4- to 6-inch long stem tip. Make sure to cut right beneath a leaf node along the stem. Remove all leaves from the lower half of the cutting.

  2. Dip the end of the stem in a rooting hormone compound, then plant it in a moist potting mix so the soil covers the exposed leaf nodes.

  3. Place the container in a plastic bag, making sure the plastic doesn't touch the cutting.

  4. Place the covered cutting in a bright, warm location until new roots develop, which will take two to three weeks.

  5. Remove the plastic and continue to grow the new plant in a bright, warm location.


Some of the more unusual cultivars might be reluctant to root, so with these, take plenty of cuttings to ensure that you get enough viable plants.


Growing Coleus

How to Grow Coleus From Seed


Modern coleus varieties sold in stores are hybrids that are almost always grown from cuttings potted up for nursery sale, but you can still find seeds of many varieties. If you will be planting the coleus in the outdoor garden, start seeds indoors about eight to 10 weeks before your last frost date.


It's easy to grow coleus from seed. It can take as long as 21 days for the seeds to germinate, so be patient. Once seedlings appear, it will take three or four weeks of warm weather to help turn them into fully grown plants.

  1. Lightly sprinkle the tiny seeds over a tray filled with potting mix, then lightly cover with a sprinkling of soil.

  2. Cover the tray with plastic and set it in a bright, warm spot until seedlings sprout, which takes about two weeks.

  3. Remove the plastic and continue to grow the seedlings while keeping the soil moist.

  4. When two sets of true leaves appear on the seedlings, carefully transplant them into their own pots and continue growing them until outdoor planting time. Make sure to harden off seedlings before planting in the garden.

From Stem Cuttings


Stem cuttings take root easily, and this is a good way to create clones of your favorites.

You can take cuttings at any time of year, and likely to do is to take them in late summer to keep indoors over the winter months so that by the time spring rolls around, and plants are ready to go.


Cut a four- to six-inch section of stem with clean pruning shears, and remove the leaves from the bottom three-quarters of the cutting.


You can either place these in water to root or in potting soil. If you’re using potting soil, dip the cut end into powdered rooting hormone, make a hole in the soil and carefully plant the cutting.


Keep the cuttings in a bright location, out of direct sun, with temperatures between 60 to 75°F. If you’re growing them in water, make sure to change it every couple of days. If they’re in soil, keep it evenly moist but not waterlogged.


After a week or two, roots should start to develop, and when they are an inch or two long, you can transplant into a container filled with potting soil. You’ll know that your cuttings in soil have successfully rooted when you see evidence of new foliar growth.


Potting and Repotting Coleus


To grow coleus in a container, start with a large pot that the plant can grow into, otherwise, you'll be repotting this fast-growing plant before you know it.


In mixed container plantings, coleus usually serves as an upright "thriller" plant in the center of the container, surrounded by "fillers" and "spillers." In colder zones, container plants are sometimes moved indoors to overwinter.


Pests and Plant Diseases


Groundhogs and young rabbits love coleus. If you can protect your plants early in the season, these pests will usually turn their attention to other plants by mid-summer. Watch out for mealybugs, aphids, spider mites, whiteflies, and slugs.


Coleus is not usually bothered by diseases unless the weather turns cool and damp. If that happens, expect to see signs of fungal diseases, such as mildew. Be careful that the plant enjoys good drainage, because standing water can lead to fungal root rot and stem rot.


Benefits of Coleus


Glaucoma – Sterile fluid extract of forskolin is known to reduce intraocular pressure, thus proving helpful in treating Glaucoma.


Asthma – Forskolin, when inhaled, decreases lung spasms, thus helping to calm the root cause of asthma.


Cardiomyopathy – Forskolin helps dilate blood vessels and enhances the heart’s blood pumping capacity.


Hypertension – Forskolin helps dilate blood vessels, thereby reducing blood pressure and thus proving to be a potent Hypertension treatment.


Psoriasis – Forskolin extract, whether ingested or applied, helps cure psoriasis.


Erectile Dysfunction – Injecting Coleus plant extract at the base of the penis along with other drugs helps improve Erectile Dysfunction in men.


It is important to note that the use of Forskolin to treat medical conditions is only a natural remedy. The information cannot replace medical advice. Therefore, it is important to seek advice from a medical practitioner.

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