Incarvillea

( in - kar - VILL - ee - uh )

At-A-Glance Information

The genus Incarvillea is commonly known as Hardy Gloxinia, Flowering Fern or Chinese Trumpet Flower. These perennial species grow from taproots or tuberous roots and produce trumpet-shaped flowers. They do best with some light shade in warmer climates and regular water. These flowers are native to China and the Himalayas. Use them in mixed beds and borders, as members of pollinator or informal gardens, or in containers.

Incarvillea Species and Varietals

The genus Incarvillea is a member of the plant family Bignoniaceae and includes 16 species. Despite the genus' common name, species are not related to those in the Gloxinia genus. They are closely related to Trumpet Vine, Crossvine, and Jacaranda. The ideal growing zones for Incarvillea are USDA hardiness zones 5a-8b. To find your zone, click here: Zone Map.

Incarvillea arguta (Chinese Trumpet Flower, Himalayan Gloxinia, Hardy Gloxinia)
Best in USDA hardiness zones 7a-10b or Sunset growing zones 4-6 and 15-24, these plants will bloom in the first year from seed. They reach up to 2-5 feet tall and 3 feet wide at maturity. Plants are a bit shrubby at the base and bloom in spring and summer. The flowers are pink or white and bloom in groups of 5-20. Great against walls or when allowed to trail down slopes or over walls. Will self-sow, but is not considered to be invasive.

Incarvillea delaveyi (Hardy Gloxinia, Chinese Trumpet Flower, Flowering Fern)
This plant is best in USDA hardiness zones 5-8 or Sunset growing zones 2-24 and reaches two feet tall and a foot wide. Plants form a rosette of leaves that produces a foot long flower stalk with rose-purple flowers with yellow throats. Blooms are present from late spring throiugh early summertime. Variety 'Snowtop' has white flowers.

Caring for Incarvillea

Plant your Incarvillea in a space in the landscape that receives full sun (between 6 and 8 hours per day is ideal). These plants can take partial shade, but will have more beautiful flowers and foliage in sunnier conditions. They prefer to be grown in soil that is well-draining, moderately fertile, and that has a pH of between 6.0 and 7.5 (slightly acidic to neutral). They can be purchased as starts from a reputable nursery, or as tubers, which can be installed directly into the garden in early spring after the last frost of the year has passed. Plant tubers between 2 and 4 inches deep with the growing tip facing upwards towards the soil surface. Space plants around 10-12 inches apart for best coverage and airflow. If local soils are particularly poor in nutrients or do not drain well, make sure to amend the planting area with plenty of organic compost before installing. Mulch around the base of plants to increase soil moisture retention, suppress weed growth, and to maintain consistent soil temperatures. Water new plantings regularly to help them establish a strong root system. At maturity, plants are somewhat drought-tolerant, able to get by on rainwater alone for much of the year. Irrigate during extended periods of drought.

Fertilize yearly in early springtime with a application of 2 inches of compost around the base of plants. Pull mulch back before applying, work the compost gently into the soil a bit, water it in, and then replace mulch. These plants are not heavy feeders, and this should be sufficient to provide the necessary nutrients for the active growing and flowering seasons. Prune off dead, damaged, or diseased foliage at any time to improve appearance and deadhead regularly to encourage repeat blooms. In fall when foliage dies back, it can be cut down to the ground and mulched over to protect tubers from freezing temperatures over the winter months. In areas with severe winter weather, dig and store tubers in a cool, dark, dry place.

Propagation

incarvillea, or Hardy Gloxinia, can be propagated either by using cuttings or from seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the cutting method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant. To propagate your Hardy Gloxinia flowers, follow the instructions below:

Propagating Incarvillea by Cutting

Gather your materials. You'll need a clean, sanitized, sharp pair of garden shears, rooting hormone, a pencil, and a 3-inch pot filled with well-draining compost or other organic material. A good substrate for propagation of cuttings is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss.
In spring or early summertime, choose the plant that you'd like to propagate. Ensure that this plant has had a good watering the night before, as this will improve the chances your cutting will take root. Cut one or more 3-4 inch portion(s) of the end of a non-blooming branch and strip the leaves off of the lower half. Make a hole in your planting medium by pushing your pencil into the soil. Dip the end of the stem in rooting hormone, and plant it in your pot. Fill in soil around the cutting to support it, but do not pack it down too much.
Moisten with water, and ensure that the pot has good drainage. Your pot should be kept in warm, sunny conditions indoors (and not in direct sunlight). Water whenever your soil is dry under the top layer. After about four to six weeks have passed, your cutting should be rooted. When you notice new growth, you'll know you have roots.
Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring, when you can transplant it to its new home. Ensure that the last frost of the year has occurred before doing this, as it can seriously damage your new flowers.

Propagating Incarvillea by Seed

Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. The best potting medium for seed germination is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss.
Harvest your seeds. The seed pods are pretty easy to spot, they're left behind after flowers have faded. Once they have dried out and begun to split open, you can harvest the seeds inside. Cut them off of the plant, placing them in a paper bag. Harvest as many as you can, and place the paper bag in a dry, cool, dark area. They will begin to split open and release the seeds contained inside. Once they have been released, take them out of the bag and put them in a container so you can work with them.
Water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes 7-14 days from sowing. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.

Propagating Incarvillea by Division
This type of propagation is relatively simple; you will need a clean shovel, mulch, fresh soil, compost, and pots (only necessary if you will be saving divided plants for transporting elsewhere). Division is best done in spring. To propagate by division, follow these steps:

Gather your materials. Using a shovel, dig up your existing plant. Start from the outside and work your way in to avoid damaging the tuber roots. Once you have worked it up out of the ground, lay it out.
Start to tease apart the roots with your fingers. Once the roots are untangled, separate your plant into segments, ensuring that each one has at least one thick section.
Prepare your pot(s) or new planting site(s) with amended, well-draining soil. You can either bring in new soil or simply amend your existing soil with compost to complete this task. Then, plant your divisions about an inch under the soil surface and water thoroughly.