How to Grow and Care for Crossandra

Crossandra Care

Here are the main care requirements for growing crossandra outdoors or indoors.

• Give crossandra bright, indirect sunlight both outdoors and indoors.
• Provide moderate moisture and high humidity levels indoors during a dry winter and outdoors in arid climates.
• Indoors, protect crossandra from cold temperatures and drafts.
• Deadhead crossandra periodically indoors and outdoors during the growing season.

Light

Crossandra thrives in bright, indirect sunlight. This can usually be achieved by planting it outside in a shady garden where it won’t be exposed to direct sunlight. Indoors, your plant will do well in a sunny north or east-facing window or with bright artificial light. Come winter, try to provide as much light as possible indoors.

Soil

A rich, peat-based potting soil that contains perlite is ideal for crossandra. When grown outdoors in the ground, work peat and compost into the soil before planting to provide good drainage and added nutrients. Crossandra likes soil that is slightly acidic (pH 5.8 to 6.5), so test the pH before planting, and use a soil conditioner if it’s not spot-on.

Water

Crossandra is very susceptible to drought and likes slightly moist soil—but not soggy—at all times. Outdoors, water this plant moderately on alternating days during the growing season. Never allow the soil to completely dry out. Reduce the amount of water in the winter to once a week, if you’re growing it as a perennial.

Indoors, you can use the same watering guide—decreasing the water in the winter to once a week—but always water your crossandra with warm water. This tropical plant dislikes the cold, and watering it with cold water may shock the roots, causing the plant to die.

Temperature and Humidity

Crossandra is very heat-tolerant and cold-sensitive, which is typical of a plant from the tropics. This plant thrives in temperatures of 70 to 75 degrees Fahrenheit. If the temperature drops below 55 degrees Fahrenheit, the plant may experience damage to its leaves.

Crossandra likes high humidity. If you live in an arid climate, mist your crossandra weekly during the growing season to provide sufficient humidity. You can raise the humidity of an indoor plant by placing it on a tray of pebbles that is filled with water, as long as the water doesn’t touch the bottom of the pot.

Fertilizer

Outdoor crossandra can be fertilized with a granular nutrient once a month. Refer to the product’s instructions on amounts, and then use slightly less than what’s recommended to avoid overfertilization.

Indoor crossandra can be fed with a liquid fertilizer, diluted to half-strength, every two weeks throughout the growing season. Cut fertilization back to once every other month in the winter for outdoor crossandra, and once a month in the winter for plants grown indoors.

Types of Crossandra

While nearly 50 species of crossandra exist in the wild, there’s only one common species in the garden industry: Crossandra undulifolia (also sold as Crossandra infundibuliformis). That said, horticulturalists have introduced some color variations of this species. Favorites include:

• Crossandra infundibuliformis ‘Mona Wallhead’: This tropical plant features salmon-pink flowers and grows to a mature height of 12 to 18 inches. It is cold-hardy, withstanding temperatures no lower than 32 degrees Fahrenheit.
• Crossandra infundibuliformis ‘Lutea’: This favorite bears rich, golden flowers and performs well in containers, where it blooms from spring until the first frost.
• Crossandra infundibuliformis ‘Orange Marmalade’: The flower boasts excellent disease and pest resistance, and is a consistent performer, showing its bright orange blooms all season long. When grown as a houseplant, this cultivar is known to bloom year-round.

Pruning

If you’re lucky enough to live in a warm climate where crossandra grows as a perennial, this plant can benefit from a healthy cutback each spring to encourage new growth. Do so before the plant starts its active growing season. Deadheading crossandra throughout the summer also helps new blooms proliferate and keeps your plant looking tidy. If you want to eliminate seed production to decrease spread, cut the spikes back before they start producing seeds.

Propagating Crossandra

Crossandra readily roots from cuttings taken early in the growing season. This is helpful, should you want to grow the same variety of plants in another part of your garden or in another garden bed.

Here’s how to grow crossandra from cuttings:

1. Gather sharp garden shears, rooting hormone powder, seed-starter mix, pots, a spray bottle, and a plant propagation mat or radiant heat floor.
2. Take cuttings early in the spring, at the start of the growing season. Make your cut slightly below a node, as new roots will grow from the node.
3. Fill your pots with the seed-starter mix.
4. Dip the plant’s cut end into rooting hormone powder, and then plant the cutting in the soil. Water the soil.
5. Provide bottom heat with a plant propagation mat or a warm floor, and mist the soil regularly until new growth emerges.
6. Once sprouted, move your new plant to its permanent location. If this location is outdoors, continue growing your cutting indoors in a pot until several sets of leaves have formed and outdoor temperatures rise. Then, carefully transplant it into the ground.
7. Potted plants will likely need to be repotted within the first month (due to rapid growth) before they begin to bloom.

How to Grow Crossandra From Seed

Crossandra blooms approximately four months after sprouting, so it’s best to start seeds indoors in late winter or early spring. To do so, take these steps:

1. Broadcast seeds across a seed-starting tray filled with seed-starting mix and cover them with a sprinkling of soil.
2. Keep the soil moist by misting it regularly with a spray bottle full of water. You can also provide a heat mat to maintain warm temperatures for sprouting.
3. Once sprouted, divide the plants into individual pots and continue growing them inside in a bright window, out of direct light, until outdoor temperatures warm.
4. Plant them into your garden bed when temperatures reach 55 degrees Fahrenheit or higher.

Potting and Repotting Crossandra

Crossandra plant is fussy and can easily succumb to transplant shock, so repot it only when necessary. For best results, repot crossandra once every three years, as this plant grows well, even when rootbound for several years.

About 24 hours before repotting, give your crossandra plant a good drink of water. Select a clay or terra-cotta pot that is approximately 2 inches larger in diameter than its current container, and then line the pot with small pebbles to ensure ample drainage. Next, carefully remove your plant from its old container and place it in the new one, backfilling it with rich organic soil that contains perlite. Water it again and return it to the same growing spot.

Overwintering

Most gardeners treat crossandra as an annual, only keeping it until its blooming season is over and then discarding it. If you choose to overwinter your plant, however, don’t necessarily expect it to bloom indoors year-round, as most varieties of this plant will go through a period of dormancy. Simply water the plant enough to maintain moist soil and wait for spring. Come spring, cut off any dead growth and move your crossandra into a slightly bigger container with fresh soil. Provide plenty of indirect, bright light for the transplant to help it adjust.

Common Pests & Plant Diseases

Crossandra plants typically don’t succumb to pests or diseases. Still, a stressed plant can become a good meal for mealybugs, spider mites, and aphids. Signs of an infestation can include tiny web-like structures on your plant, as well as clumps of white powdery residue or visible insects. Treat infestations as soon as possible to prevent them from spreading to the rest of your plants. As always, start with the least toxic treatment option first, like spraying offenders with a blast from your garden hose, before progressing to products like a 70 percent diluted isopropyl alcohol solution or harsh chemicals.

Look for fungal issues, such as powdery mildew or gray mold (Botrytis). Fungicides used early in the season will help. Planting flowers in the full sun is also helpful.

How to Get Crossandra to Bloom

Bloom Months

Outdoors, crossandra will provide long-lasting flowers from late spring to autumn under the right conditions. As a houseplant, it can bloom just about all year under correct indoor conditions.

What Do Crossandra Flowers Look and Smell Like?

Crossandra produces clusters of unscented tubular flowers in colors such as salmon, and shades of red, orange, yellow, and pink. Rain may damage the bright, delicate flowers but otherwise, they attract butterflies, bees, and other pollinators, making it a good addition to any butterfly garden, as it blooms all season long.

How to Encourage More Blooms

Make sure your crossandra gets dappled light during the day in a spot that will not get too hot. Severe low-light conditions will significantly decrease the plant’s ability to produce flowers. Let your crossandra dry out just slightly before watering, as this will spur new blooms.

Deadheading Crossandra

Deadheading will also initiate new buds and flowers, so tidy your plant throughout the growing season for the best results.

Common Problems With Crossandra

Crossandra is a rewarding, low-maintenance plant once the right conditions are met. In the meantime, always look out for these issues that may crop up.

Yellowing and Rotting Leaves

Overwatered crossandra plants can fall victim to root rot, evidenced by yellowing and rotting lower leaves and a sudden loss of flowers. Allow most of the soil to dry out in between waterings, preventing a pool of standing water from accumulating beneath the pot.

Foliage Wilting

Wilting foliage often indicates an inconsistency in watering the plant. This could happen if you are trying to dry out overwatered soil and then it suddenly dries out. Check the plant for root rot if you have wilting foliage.

Flowers Dropping

If your crossandra is suddenly dropping buds or flowers, it is likely overwatered. To avoid this, use a porous clay or terra-cotta pot with good drainage, and stick to recommended watering protocols for both garden and houseplants.

Dark and Discolored Foliage

Crossandra is very finicky about water temperatures. Watering your plant with cold water may cause root shock, which can lead to dark discolored leaves and plant death. Always water indoor plants with room temperature water and outdoor plants are best watered during the heat of the day.