Coleus Guide: How to Grow and Care for Coleus Plants (2024)

Coleus plants, known for their vibrant, colorful foliage, are an attractive and popular choice among gardeners. They are a member of the mint family, assertively displaying their square stems and beautiful oval leaves.

Their variety of patterns and colors, ranging from burgundy to bright neon shades, can uplift the beauty of any landscape.

These plants, although tender perennials, are often grown as annuals or houseplants, making them an incredibly versatile addition to your gardening collection.

Some coleus varieties have a strikingly upright growth habit, while others cascade beautifully, making them ideal for adding life to plain walls or corners.

Use them to create layers in your garden or use them as ‘fillers’ and ‘spillers’ in containers to maximize their impact.

One unique feature of the coleus plant is its flower spikes that appear in late summer, adding an extra flair to their overall appeal.

However, it’s their dense foliage that steals the show, with patterned varieties like the ‘fishnet stockings’ being a favourite among gardening connoisseurs.

Coleus is a hardy plant, capable of thriving in varying light conditions. They can tolerate anything from indirect light to full sun, making them a flexible choice for many indoor and outdoor settings.

However, for the best and most vibrant leaf color, a morning sun location with some afternoon shade works best.

As a master gardener, they have always amazed me. In this article, I’ll share with you everything you need to know about growing and caring for coleus plants.

Botanical Name: Coleus

Common Name: Plectranthus scutellarioides

Family: Lamiaceae

Plant Type: Herbaceous perennial (usually grown as an annual)

Hardiness Zones: 10 – 11 (USDA)

Sun Exposure: Part shade to full shade

Soil Type: Rich, moist, loose soil, well-drained

Soil pH: Slightly acidic to neutral (6.0 to 7.0)

Bloom Time: Seasonal

Flower Color: Blue to white

Native Area: Asia

Coleus Plant Care

Coleus plants are a hardy member of the mint family, known for their vibrant, colorful foliage with patterns of green, pink, burgundy and cream.

These annuals are perfect as container plants or incorporated into landscape design, providing dense foliage and a burst of color in both full sun and full shade conditions.

The time of planting should be after the last frost date, in well-draining soil to prevent root rot. Regular application of water-soluble fertilizer will encourage lush growth and frequent water during dry spells will keep these plants looking their best.

When cultivating in a pot, drainage holes are necessary to eliminate excess water, as well as prevent the root ball from sitting in still water.

Light

Coleus plants are versatile and adaptable, thriving in varying light conditions. They enjoy morning sun and afternoon shade, perfect for those sunny yet cool locations in your garden.

While they can withstand full sun, their colorful foliage can often become more vibrant when grown in partial to full shade. However, it’s important to note that too much shade can lead to less vivid leaf colors.

For indoor coleus as houseplants, they prefer bright, indirect light. Indoor coleus that doesn’t receive adequate light may stretch and become leggy, so adjust light conditions as needed for your coleus to remain dense and upright.

Soil

Coleus plants have a fondness for good-quality, well-draining soil, which is essential to prevent root rot. These plants demand good drainage as they despise wet feet and water-saturated soil can bring harm to their roots causing rot.

They thrive in compost-rich soil which supports their lush growth and dense foliage. Adding organic matter to the soil at the time of planting will further enhance the growth.

If you’re planting in a pot, ensure it has drainage holes at the bottom to allow excess water to escape. The top inch of soil is expected to be dry between watering cycles.

Water

Proper watering is crucial in the care of coleus plants. These annuals prefer moist soil, necessitating frequent water, especially during dry spells in late summer.

However, they’re susceptible to root rot, so it’s essential to use pots with good drainage holes and employ well-draining soil to prevent excess water accumulation.

The top inch of soil should be allowed to dry out before watering again. Reducing watering during fall and winter months can help prevent over-saturation and the woes of overly damp root balls.

Temperature and Humidity

Coleus plants, being tropical in nature, thrive best in temperatures between 60 and 85 degrees Fahrenheit.

They require a relatively high level of humidity to maintain their colorful foliage. During winter or dry spells, consider placing a tray of water near your houseplants to increase the humidity in the room.

Typically, coleus doesn’t tolerate cold temperatures, so bring your outdoor specimens indoors before the first frost date.

Lastly, don’t forget to protect your coleus from drafts, which can dramatically fluctuate the temperature and humidity levels, causing stress for your plant.

Fertilizer

Coleus plants, vibrant annuals renowned for their colorful foliage, require frequent feedings of a water-soluble fertilizer.

This member of the mint family with its square stems blooms best when fertilized every two weeks during the growing season—from the time of planting after the last frost date until late summer when flower spikes may start to appear.

A balanced fertilizer of good-quality can promote the production of their unique foliage that ranges in hues from burgundy to fishnet stockings.

But remember, over-fertilization may lead to an overgrowth of leaves, reducing the plant’s distinctive square stems and upright structure.

As the coleus plant is mostly grown for its decorative leaves, ensuring proper fertilization enhances the overall display in your landscape.

Pruning

Pruning is vital for coleus plants to maintain dense foliage and promote more colorful leaves. Start by pinching back the growing tips early in the season to encourage a bushy habit.

Use your fingers to pinch off the top inch of stem just above a leaf node. In late summer, remove the flower spikes from your coleus as they emerge to keep the plants producing leaves and maintain their upright growth.

Regular pruning also helps mitigate pests like whiteflies, aphids, and spider mites, which often hide under leaves and stems.

Lastly, whenever you notice any unhealthy, yellow, or wilted leaves, prune them off to prevent any potential spread of disease.

Types of Coleus

• Wizard Series: The Wizard Series is a group of coleus plants known for their colorful foliage. These houseplants thrive in indirect light and fare well as container plants.

• Kong Series: The Kong Series are hardy annuals that thrive in full shade, prefer good-quality soil, and exhibit a bright mix of colors. They make for great landscape plants.

• Black Dragon: Black Dragon coleus is a unique variety with burgundy leaves contrasted by a fishnet stocking pattern.

• Premium Sun Series: Premium Sun Series are colorful coleus plants characterized by sturdy, upright stems and thick, bright leaves.

• Fairway Series: Fairway Series is a selection of compact and well-branched perennial coleus, perfect as spillers in hanging baskets or as standout solo plants.

How to Plant Coleus From Seed

Time of Planting

The first step towards successful coleus cultivation is understanding the optimal time of planting – which is definitely after the last frost date.

This colorful foliage plant is tender and susceptible to cold climates, thus they thrive best as annuals in warm temperatures.

Choosing the Right Pot

Before planting, you need to make sure you have the right pot for your coleus plants.

A good-quality pot with ample drainage holes is essential to prevent root rot – a common problem caused by excess water and lack of good drainage.

A well-draining soil is also key to healthy coleus plants.

Planting Process

Prior to placing the seeds, fill your pot with a well-draining soil, leaving about an inch from the top.

Sow the seeds within the soil, ensuring they are not deep as coleus seeds need light to germinate. Once you have sowed your seeds, lightly water them.

How to Propagate Coleus

Step 1: Choose a Healthy Coleus Plant

When propagating coleus, always choose a healthy parent plant with vibrant, colorful foliage. Look for square stems, which shows the coleus plant is a member of the mint family.

Check for signs of insects such as aphids, whiteflies, and spider mites. These pests can affect the health of the plant and interfere with the propagation process.

Step 2: Cutting Preparation

Cutting stems is at the heart of propagating coleus plants. Begin by making a clean cut just below a leaf node using good-quality pruning shears.

Each cutting should consist of the stem with at least 2 sets of leaves – snip off the lowest pair to create the stem root. This cutting (minus its bottom leaves) will then be used for propagation.

Step 3: Rooting the Cutting

Once you’ve prepared your stem cutting, place it in a pot filled with well-draining soil. Good drainage is essential to avoid root rot from excess water.

The pot should have drainage holes, as stagnant water is not good for the plant’s root health. The top inch of soil should cover the node where the lower leaves were removed.

Step 4: Watering and Fertilization

After planting, water the cutting thoroughly, ensuring no water pools around the stem root.

Watering should then remain consistent without making the soil overly soggy. Ensure the cutting is in indirect light and apply water-soluble fertilizer once roots have formed visibly.

Step 5: Ongoing Care

Care for your new coleus plant as per its mature counterparts. These are annuals, but can also be grown as perennials indoors as container plants or houseplants.

As they grow, you may notice growths known as flower spikes – pinch these off to encourage denser foliage.

Coleus prefer morning sun and afternoon shade. In regions with harsh summers, coleus may appreciate a position in full shade.

Transitional care may be necessary, moving it towards full sun over the course of a few weeks after the last frost date.

How to Pot or repot Coleus

Step 1: Selection of Appropriate Pot

When deciding to pot or repot a coleus plant, your choice of pot plays a significant role.

It’s best to select a pot with good-quality that has drainage holes. Why? Good drainage is essential to prevent root rot, a condition that occurs when a plant’s roots sit in excess water, causing them to decay.

A well-draining soil and pot can ensure that excess water is removed, protecting the integrity of the root ball and overall health of the plant.

Step 2: Preparing the Potting Mix

Before placing your coleus in its new pot, prepare a well-draining soil mix suitable for container plants. This is usually a blend of garden soil, compost, and perlite or vermiculite.

For coleus, a member of the mint family, it’s beneficial to use a soil-rich compost since it enjoys a nutrient-rich environment.

Remember, the soil should be able to retain moisture but still drain well, making it perfect for periods of dry spells.

Step 3: Time of Planting

The best time to plant or repot annuals like Coleus is after the last frost date, generally in late spring or early summer. Coleus plants are not hardy, so they must be protected from cold temperatures.

However, if you’re growing Coleus as a houseplant, you can pot or repot at any time of the year, provided you can offer the plant with the right care requirements, including light, water, and temperature.

Step 4: Planting the Coleus

Before planting, gently remove the coleus from its current container, taking care not to damage the root ball.

Place the plant in the new pot, ensuring it’s centred and upright. Fill in around the stem root with the prepared soil, careful not to cover the stem or leaves.

A useful tip for container plants is to use the ‘thriller, filler, spiller’ method: an upright ‘thriller’ plant (the coleus), surrounded by ‘filler’ plants to cover the soil, and trailing ‘spillers’ to hang over the sides of the pot.

Common Pests and Plant Diseases for Coleus

Whiteflies

These small insects can often be found on the underside of coleus plants’ leaves.

Whiteflies suck sap from the plant, leading to yellowing and a decrease in overall plant vigor.

Regular monitoring and the use of water-soluble insecticides can help keep these pests at bay.

Aphids

Aphids are common pests on coleus and many other ornamental plants.

These small pests feed on the sap in the stems and leaves of the coleus, leading to yellowed leaves, reduced growth, and potential disease transmission.

It’s crucial to get rid of aphids promptly to prevent them from spreading to other plants.

Root Rot

Root rot is a widespread disease of coleus, often arising due to waterlogged soil conditions.

This is especially common in container plants where good drainage is crucial. Without proper drainage holes, the excess water cannot escape, making the conditions ideal for root rot.

It is essential to use a good-quality, well-draining soil to prevent this, and avoid overwatering.

Spider Mites

Spider mites can cause significant damage to coleus plants, manifested through yellowing leaves, slow growth, and eventual plant death.

Spider mites are attracted to plants in dry conditions, so providing the coleus with frequent water can help deter these pests.

However, be careful not to overwater, as this can lead to problem such as root rot.

Mealy Bugs

Mealybugs are pests that can infest and damage a wide range of houseplants, including coleus.

They feed by sucking sap from the plant, which can lead to wilting, yellowing and growth stunt. Mealybugs also excrete a sticky substance called honeydew, which can lead to sooty mold.

Removing them with a soft cloth and soapy water, or using a water-soluble insecticide, can ensure that your coleus continues to thrive.

Common Plant Problems and Solutions for Coleus

Brown Tips

Brown tips on the leaves of coleus plants can be a sign of inadequate water supply, especially during dry spells. The solution is frequent water, ensuring that the top inch of soil is moist, but not soggy.

Always check to wait for the top inch of soil to dry out before watering again. Too much water can lead to root rot, so drainage holes in your pot are vital to provide good drainage.

Yellowing Leaves

Yellowing leaves often indicate that your coleus plant is getting too much sun. Although coleus plants are hardy, they prefer indirect light and afternoon shade.

Consider moving your container plants to a location with softer light or creating shade for them during peak sunlight hours.

Stunted Growth

Stunted growth in coleus can be caused by a lack of nutrients, compacted root ball, or pest problems like aphids and spider mites.

A well-balanced, water-soluble fertilizer can be added during the time of planting and regularly thereafter for continuous nutrient supply.

For pest issues, you may use an organic insecticide to rid your plant of unwanted pests.

Leggy Plant

A coleus plant may become excessively ‘leggy’, with long, thin stems and sparse leaves, if it’s not receiving enough light, or if it’s too crowded.

Providing morning sun and regular pruning of the growing tips to encourage more dense foliage can help rejuvenate your plant’s upright stance.

Wilting and Root Rot

Wilting or root rot might indicate over-watering or inadequate drainage.

Ensure that your coleus plants are in a good-quality pot with plenty of drainage holes, and water only when the top inch of soil feels dry to the touch.

Using well-draining soil can also help prevent water logging and hence root rot.

Pale or Bleached Leaves

Pale or bleached leaves are usually a sign that the plant is getting too much direct sun.

Coleus may be a member of the mint family with square stems, but it doesn’t enjoy full sun exposure.

If situated in full sun, the colorful foliage of burgundy, oval leaves on the ‘Fishnet Stockings’ variety would fade.

Instead, locate your plant in a spot where it receives plenty of indirect light, such as in full shade or under larger, more sun-tolerant annuals or perennials in the landscape.

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