Coleus are bushy and compact herbaceous shrubs from the Lamiaceae or mint family and is native to tropical and subtropical regions from southeast Asia to Australia.
This bushy, woody-based evergreen perennial has a mounting growth habit and is widely grown for its highly decorative variegated leaves with bright leaf colors, margins, and patterns.
Anyone who has ever tried rooting Coleus blumei from cuttings knows how easy it is to grow.
Many of us got our first house plant – a coleus plant by propagating coleus through stem cuttings.
But, did you ever try growing coleus from seed for a really plentiful supply and to avoid having to winter over so many?
How To Propagate Coleus From Seeds
Coleus propagation from seeds is easy… it’s almost like growing radishes! Growing coleus from seeds makes it a great perennial if you live in warmer zones.
Coleus seeds are a little larger than those of petunias.
When do you start Coleus seeds indoors?
Although coleus seeds may be sown at any time of the year when warmth can be furnished, seeds sown during February will produce plants of just the right size for outdoor use in May. Perfect for the spring growing season.
You may also sow seeds indoors 6 to 8 weeks before the last frost in your USDA hardiness zone.
NOTE: Coleus does not like cold. Plants outdoors after the last frost date.
Coleus seedlings introduce you to all types of coleus varieties that exhibit diverse colors, leaf forms, and markings.
This makes growing coleus seedlings particularly interesting. You will wonder what possible cross or hidden ancestry produced the variations.
By the time most coleus plants start to bloom, they are determined to bloom.
No amount of pinching out flower buds will long delay the inevitable sprouting of buds all over the plant.
Allow some bloom stalks to mature seed, trim the whole plant back, or start new plants by propagating coleus stem cuttings.
Some types of coleus flowers appear quickly; other varieties of plants grow the whole long growing season of a Florida summer without so much as a bud.
Naturally, the more kinds are blooming at once, the more possibilities for crosses to produce plants of different appearance.
Related Reading: Coleus Care Questions & Answers
For example, a plant with plain smooth leaves green, with tan center marking and pinkish reverse, others with slender, partially crumpled brightly colored leaves, and others with ruffled leaves.
I’ve had seedlings with slender crumpled leaves showing the green and tan color and ruffled ones in various combinations of pink and tan.
Coleus seed scatters easily, and the pods should be removed as soon as they turn slightly yellow.
When dry, the seed may be rubbed out between the hands and freed of chaff by blowing lightly.
Seed packets may be obtained from practically any reputable seed house as well.
Tips On Planting Coleus Seed
Since coleus seed is fine, they must be planted in well-drained soil, in flats or other containers that may be protected from hot sunshine and slashing rain.
There are several options to use as a seed starting mix or planting medium to grow coleus seed.
- Use a planting medium like one used for growing and caring for African violets.
- Light-rich soil, but not over-fertilized, with topsoil sifted through a piece of screen wire, so it is quite fine.
Plant in a pot, three or four-inch pots, or any other type of container with plenty of drainage holes.
Containers should be filled well so seedlings will not become full of stems reaching for the bright light.
After the soil is quite smooth and wet thoroughly, sprinkle the seed very thinly on top of the moist soil, and sift over them just enough of the finest soil to hide the seed from sight.
An easy method for planting the seed is to mix it with a bit of finely screened peat moss or clean, dry sand and sprinkle it over the seedbed.
Do not cover the seed, but give the top of the bed a gentle firming with the palm of your hand to remove any air pockets and give depth. Set the container in warm water so that moisture comes from the bottom and will not disturb the seed.
When the water has reached the top of the soil, remove the pot from the water and place a piece of glass or cellophane over the top to conserve moisture.
Place the container in partial shade and warm place to await germination. Keep the soil moist. Coleus seeds will not come up well if they dry out or if soil temperatures drop much below 60° degrees.
If the seed is fresh and conditions satisfactory, the seed will begin to germinate by the fifth day.
The seedlings have a characteristic appearance and are easily recognizable once one has seen them.
They should immediately have plenty of light, with direct sunlight when not too hot, but at no time should the potting mix dry out, as the plants have very shallow roots.
Transplanting will be necessary as soon as they begin to crowd each other in the seedbed.
One sign your coleus seed is ready for transplanting is when it finally has two sets of true leaves.
Check out – When Should You Thin Seedling and Why?
It’s incredibly easy to transplant coleus as anything you’ll ever grow. Once they have two sets of leaves, put them in individual pots or planters or group them in a flat a few inches apart.
Placing a plant tag will be helpful as a location marker after transplanting them. Don’t forget to use soil amended with organic matter like compost in your planting area matter to provide a good balance of nutrients and an ideal pH level.
Moreover, you can mulch your plant stems to prevent possible root rot.
Video: Starting And Growing Coleus Seeds
Large or small, coleus should never be crowded, and seedlings should be transplanted promptly to prevent crowding. They are easily moved at any age.
Plants should be protected from heavy rains, very hot sunlight, and high winds, for some time, and those with creepy foliage are subject to storm damage at any age.
Seedling coleus usually produces well-shaped plants with uniform branches. Bright colors do not develop until the plants are some size, though occasionally, a distinctive leaf pattern will be unmistakable when the first true leaves appear.
Plants unsatisfactory in leaf form or color should not be permitted to bloom, though they may be kept for a single season.
Even among seedlings from the showiest sorts, some dull or stemmy plants will result, and a few plants will remain pale and spindly with the same treatment under which others become strong and husky.
By the time coleus seedlings are two inches tall, they may receive the same care given to any other coleus of their particular type.
Coleus leaves vary in size from fingerprint measure to those almost as broad as a dinner plate. They may be satiny smooth, ruffled, crepey and pebbly, scalloped, or pivoted in texture.
Colors range from velvety purple-black, with green edges, to various white and green combinations. There are shades of brown, like pansy faces, and all shades of red and pink, combined with green, yellow, and cream.
There is a fascination with coleus, which increases as one works with them.
Uses of Coleus
When seedlings have four to six leaves, you’re ready to use coleus-like paint from a seed tray wherever a spot of rich color and velvety texture is needed.
Almost no two seedlings will have the exact same leaf pattern or coloring. At this time, pinch out the top two new leaves to encourage branching and a more sturdy, bushy plant.
Coleus is ideal for formal gardens, in a border, or to heighten the effect of some blossoming plants by repeating their flower hue. I’ve seen this done effectively in a garden surrounding the museum in Denver, Colorado.
Coleus plants cannot be excelled for use in planter boxes, urns, porch boxes, or hanging baskets outdoors.
In Missouri last summer, I saw a most striking planting of assorted coleus seedlings on the east side of a shade garden where they received full sun until early afternoon.
On either side of the garden entrance, two white ornamental iron urns were set, planted with coleus whose leaves were of the richest wine velvet with a tiny leaf edge of green.
To take up the reddish-purple of the colorful leaves, this landscaper was smart in using something unusual… The Magic Flower Plant – Achimenes.
When you set seedlings outdoors, they may need to be shaded for a few days, but once they are established, they can stand plenty of sunlight, and it seems to make their colors more vivid.
However, the best outdoor use of coleus is to bring color to a spot not reached by the sun – for, unlike so many plants, use coleus as a shade plant.
The best window garden specimens are often those grown against a plate glass shop window or one given sole domain in someone’s bright picture window.
For such individual use, good Coleus cultivars are those whose foliage colors appear deep, soft red edged delicately in light green.
Specimen container garden plants should be turned frequently, and judicious pinching of new growth stimulates denseness.
Related: Are Coleus Poisonous?
Likes and Dislikes
Coleus like fertile soil and liberal doses of organic fertilizer such as fish emulsion or liquid food (water-soluble plant fertilizer). Care should be taken not to overwater.
Just provide adequate watering, especially during dry spells.
While plants do grow quickly and use much moisture, extreme wetness, especially if conditions are cool, will cause rotting.
Coleus has one foe – the cottony mealybug. If your plants get a good case of this gnawing little horror, pull out the whole mess, then buy a packet of seeds and grow some new plants.
Aside from mealybugs, other common insect pests that attack Coleus include aphids, spider mites, whiteflies, and slugs.
Try coleus indoors, particularly in your busiest living area, for they are wonderfully savable. No cause for concern when overzealous pets or youngsters in a fast game of indoor ball devastate your houseplants.
It’s also important to keep weeds under control. You can use a rake to weeds, clumps, and plant debris that may interfere with your plant.
If they’re coleus, you can pick up the pieces, stick them in water in a glass or jar, and soon you’ll have rooted coleus cuttings ready for pot soil. And quite decorative, these cuttings are in process!
Even a badly battered mature coleus plant will put out new growth, particularly if it can be moved to an outdoor location.
The annual blue coleus is ideal for the casual grower who is more interested in creating a pleasing decorative effect than in the plants themselves. As they are easy to grow, this also makes a great option for starters and casual gardeners.
They are a standby as a color accent in all foliage planting, and they are encouraging material for children or any beginning gardener. No waiting for blooms; with coleus, the color is there from the first!