Incarvillea, commonly known as hardy gloxinia or Chinese trumpet flower. These plants offer beautiful, trumpet-shaped blooms and are a lovely addition to the garden, especially for those seeking something a bit different from the usual perennials.

What Makes Incarvillea So Special

• Exotic-Looking Flowers: The most striking feature of Incarvillea is its large, trumpet-shaped flowers, which resemble those of gloxinias (hence the common name "hardy gloxinia"). These flowers come in shades of pink, rose, red, white, and sometimes yellow.
• Long Bloom Time: Many Incarvillea species and cultivars have a relatively long bloom period, often starting in late spring or early summer and continuing for several weeks, sometimes with sporadic reblooming later in the season.
• Attractive Foliage: The foliage is also attractive, with deeply divided, fern-like leaves that provide a nice textural contrast to the flowers.
• Hardiness: Despite their exotic appearance, many Incarvillea species are surprisingly hardy, tolerating cold temperatures (down to USDA zone 5 or even 4 with protection). This makes them accessible to gardeners in a wider range of climates.
• Uncommon: They are less commonly grown than many other perennials, making them a bit of a "collector's plant" and a conversation starter in the garden.

Description and Details

• Growth Habit: Herbaceous perennials, typically forming clumps.
• Stems: Erect or ascending stems, often somewhat fleshy.
• Leaves: Opposite or whorled, pinnately compound (divided into leaflets), with toothed or lobed margins. The foliage has a fern-like appearance.
• Flowers: Large, trumpet-shaped (tubular), five-lobed flowers. They are typically borne in terminal racemes (elongated clusters) or panicles (branched clusters).
• Fruit: Elongated, capsule-like fruits containing numerous seeds.
• Size: Varies depending on the species and cultivar but generally ranges from 30-90 cm (1-3 feet) tall, with a similar spread.

Commonly Cultivated Species

• Incarvillea delavayi (Hardy Gloxinia, Chinese Trumpet Flower): The most commonly grown species. Native to southwestern China. Flowers are typically rose-pink to magenta. Hardy to USDA zones 5-7.
• Incarvillea mairei: Similar to I. delavayi but often shorter and with larger flowers.
• Incarvillea arguta: Native to the Himalayas. Flowers can be pink, white, or yellow.
• Incarvillea lutea: Has yellow flowers.

Native Habitat

• Origin: Native to central and eastern Asia, particularly China and the Himalayas.
• Typical Habitats: Found in mountainous regions, often in rocky or well-drained slopes, meadows, and open woodlands.

Landscaping Design Tips

• Borders and Beds: Excellent for the middle of the border, providing height and color.
• Rock Gardens: Their preference for well-drained soil makes them suitable for rock gardens.
• Cottage Gardens: Their slightly exotic appearance fits well into the informal style of cottage gardens.
• Mixed Plantings: Combine them with other perennials and shrubs, using their bold flowers and fern-like foliage to create interesting contrasts. Good companions include plants with contrasting foliage textures or flower colors.
• Containers: Can be grown in containers, especially the more compact varieties.
• Cut Flowers: The flowers can be used as cut flowers, although they may not be exceptionally long-lasting.

Planting and Care

• Planting:
• Timing: Plant in spring or early fall.
• Spacing: Space plants 30-45 cm (12-18 inches) apart.
• Soil: Prefers well-drained soil that is moderately fertile. Amend heavy clay soils with compost or other organic matter to improve drainage. A slightly acidic to neutral pH is ideal.
• Light: Full sun to partial shade. In hotter climates, they may benefit from some afternoon shade.
• Depth: Plant with the crown (where the stems meet the roots) at or slightly below the soil surface.
• Care:
• Watering: Water regularly during the first growing season to establish a deep root system. Once established, they are relatively drought-tolerant, but they will perform best with consistent moisture, especially during dry periods. Avoid overwatering, which can lead to root rot.
• Fertilizing: A light application of balanced fertilizer in spring can be beneficial. Avoid over-fertilizing, which can lead to excessive leafy growth and fewer flowers.
• Deadheading: Remove spent flowers to encourage continued blooming and prevent seed formation (unless you want to collect seeds).
• Mulching: Apply a layer of mulch around the plants to help retain moisture, suppress weeds, and protect the roots in winter (especially in colder climates).
• Winter Protection: In colder climates (USDA zones 4-5), provide a thick layer of mulch in winter to protect the crown from freezing temperatures.
• Pest and Diseases: Generally, pest and disease resistant. Slugs and snails may occasionally feed on the foliage. Root rot can be a problem in poorly drained soils.
• Propagation: Can be propagated from seed or division.

Taxonomy

• Kingdom: Plantae
• Phylum: Tracheophyta
• Class: Magnoliopsida
• Order: Lamiales
• Family: Bignoniaceae (Trumpet Creeper family)
• Genus: Incarvillea

Morphology

• Root System: Fleshy, tuberous roots.
• Stems: Erect or ascending, often somewhat fleshy.
• Leaves: Opposite or whorled, pinnately compound (divided into leaflets), with toothed or lobed margins.
• Flowers: Large, trumpet-shaped (tubular), five-lobed flowers. The corolla (petals) is fused into a tube, and the lobes are often flared.
• Fruit: Elongated, capsule-like fruits containing numerous seeds.

Other Insights for Gardeners

• Hardiness Variations: Hardiness can vary depending on the species and even the specific cultivar. Check the hardiness zone information for the particular plant you are considering.
• Seed Germination: Incarvillea seeds can be somewhat erratic in germination. Fresh seeds generally germinate best. Cold stratification (a period of chilling) can improve germination rates.
• Toxicity: Some sources indicate that Incarvillea plants may be mildly toxic if ingested. It is best to keep them out of reach of children and pets.
• Deer Resistance: Generally considered deer-resistant, although deer may browse on them if other food sources are scarce.

In conclusion, Incarvillea offers gardeners a chance to grow something a bit different and exotic-looking, yet surprisingly hardy and relatively easy to care for. Their beautiful trumpet-shaped flowers and attractive foliage make them a valuable addition to borders, rock gardens, and other garden settings. With proper planting and care, these "hardy gloxinias" can provide a touch of the tropics to temperate gardens.