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 perennials have trumpet-shaped flowers and do best with some light shade in warmer climates and regular water. These flowers are relatives of the Trumpet Vine (Campsis) and are native to China and the Himalayas. Use these flowers in mixed beds and borders, as members of pollinator, informal, or in containers. 

Incarvillea Species and Varietals

The genus Incarvillea is a member of the plant family Bignoniaceae and includes 16 species.The ideal growing zones for Incarvillea vary depending on the species. For more information, see the descriptions below. To find your zone, click here: Zone Map.

Incarvillea arguta (Chinese Trumpet Flower)
Best in zones 4-6 and 15-24, this plant will bloom in the first year from seed. Gets 2-5 feet tall and 3 feet wide. It is a bit shrub-like at the base, and blooms 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)
This plant is best in zones 2-24 and reaches two feet tall and a foot wide. Forms a rosette of leaves that produces a foot long flower stalk holding rose-purple flowers with purple-marked yellow interiors. This species blooms in late spring and early summertime. Variety 'Snowtop' has white flowers. Mulch around plants right after the first frost of the year.

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
  1. 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. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) peat moss and horticultural-grade sand or grit sand.
  2. 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.
  3. 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. 
  4. 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
  1. 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. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) peat moss and horticultural-grade sand or grit sand. You will also, after a few weeks, need individual 3-inch pots for each seedling that grows. 
  2. 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.
  3. 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.
  4. 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.
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Propagating Incarvillea by Division
This type of propagation is relatively simple; you will need a clean shovel, mulch, fresh soil (any kind will do, though it does need to be well-draining), compost, and pots (only necessary if you will be saving divided plants for transporting elsewhere). Division is best done in spring or fall (after the plant has entered dormancy and been cut to the ground, but before it has begun its new spring growth), and needs to be done every four to five years regardless of whether you have the goal of propagating the plants for best performance. To propagate by division, follow these steps:
  1. Dawn your protective gear and 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.
  2. Start to tease apart the roots with your gloved fingers. Once the roots are untangled, separate your plant into segments, ensuring that each one has at least one thick tuberous section.
  3. 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 divided tubers about an inch under the soil surface and water thoroughly.

Problems and Pests

Incarvillea, or Hardy Gloxinia, plants can have issues with the following pests and diseases in the landscape:
  • Slugs and Snails
  • Powdery Mildew
  • Aphids
  • Crown and Root Rot
For more information on these issues, including how to treat and manage them, consult the following links:
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Gallery

Camellias are great candidates to be grown as container plants on your patio.
A field of thea sinensis
Camellia hiemalis 'Shishi Gashira'

Videos

Learn how to grow Incarvillea.
How to hand-pollinate Hardy Gloxinia.

Resources

How to Grow and Care for Incarvillea (Hardy Gloxinia)
Incarvillea delavayi (Hardy Gloxinia)
Wikipedia: Incarvillea
The New Sunset Western Garden Book: The Ultimate Gardening Guide (2012) - Page 374, Incarvillea
If you have any questions, comments, concerns, or photos you’d like to add to the gallery, please let me know by sending me a message using the button below!
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