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CATASETUM expansum

Image of Catasetum expansum

James Burghardt

Family

Orchidaceae

Botanical Name

CATASETUM expansum

Plant Common Name

Catasetum Orchid, Orchid

General Description

Referred to as the expansive catasetum orchid, this species has an expansive blooming season as well as large stems covered with green, white or yellow blooms. This species is native to the dry, but seasonally wet, highland forests of Ecuador. It's an winter deciduous epiphyte (grows on trees) that forms a perennial clump.

"Catasetum" is a Greek compound word meaning "down bristle." This orchid genus is unique in having different gendered flowers on the same plant. Male flowers have an antenna-like trigger device that snaps pollen onto the backs of visiting bees. These pollen-covered insects then find a hooded female flower and unknowingly pollinate it. Because male and female flowers look different, people may have considerable difficulty identifying plants, especially if growing conditions or gender diphasy prevents the development of both flower genders on a single plant at the same time.

The expansive catasetum orchid produces pointed, fleshy pseudobulbs that display thin, soft, pleated leaves of medium green. Leaves shrivel and drop away by fall as the plant enters a natural dormancy period through the cool tropical winter dry season. Flowering occurs from late spring to early winter, usually when leaves are still present. An arching flower stalk rises from newly developing pseudobulbs, and carries either all male flowers or all female flowers. A plant can produce both flower types, but always on separate flower stalks. Male Catasetum flowers are showier with longer petals that spread more widely than the upside-down cup-like flowers of their female counterparts. If light is low, a plant may only produce male flowers. Very bright light encourages both female and male flowers to be produced. Expansive catasetum's flower color varies from plant to plant, anything from yellow to white or green. Some are solid colored, while others have maroon dots.

Where hardy, expansive catasetum can be grown outdoors mounted on a tree trunk or in a hanging basket or slatted wood box. In frostier climes it should be grown indoors in a warm greenhouse or very bright sunroom. Plant in coarse bark nuggets for orchid culture and provide full sun to very bright dappled shade. Too little light prevents good flowering. Water the orchid freely when new growth and foliage is present (mid-spring to fall). From fall to spring, water very little. Do not begin spring watering until new leaf growth reaches two inches (5 cm) long. Good air circulation with high humidity will encourage good growth. Fertilize weekly with a dilute solution of balanced fertilizer from spring to late summer. Don't be alarmed when the leaves turn yellow in fall; this is the signal dormancy has set in and to markedly reduce watering.

Characteristics

  • AHS Heat Zone

    11 - 9

  • USDA Hardiness Zone

    10 - 13

  • Sunset Zone

    H1, H2, 22, 23, 24

  • Plant Type

    Epiphyte

  • Sun Exposure

    Partial Sun, Partial Shade

  • Height

    18"-24" / 45.7cm - 61.0cm

  • Width

    20"-28" / 50.8cm - 71.1cm

  • Bloom Time

    Late Spring, Early Summer, Summer, Late Summer, Early Fall, Fall, Late Fall, Early Winter

  • Native To

    South America

Growing Conditions

  • Soil Drainage

    Well Drained

  • Growth Rate

    Slow

  • Water Requirements

    Average Water

  • Habit

    Clump-Forming

  • Seasonal Interest

    Spring, Summer, Fall

Ornamental Features

  • Flower Interest

    Showy

  • Flower Color

    White, Yellow, Green, Light Yellow, Yellow Green, Dark Red, Light Green, Chartreuse

  • Flower Color Modifier

    Multi-Color

  • Foliage Color (Spring)

    Green, Light Green

  • Foliage Color (Summer)

    Green, Light Green

  • Foliage Color (Fall)

    Yellow, Green, Light Green

  • Fragrant Flowers

    Yes

  • Fragrant Fruit

    No

  • Fragrant Foliage

    No

  • Bark or Stem Fragrant

    No

  • Flower Petal Number

    Single

  • Repeat Bloomer

    No

  • Showy Fruit

    No

  • Edible Fruit

    No

  • Showy Foliage

    No

  • Foliage Texture

    Coarse

  • Foliage Sheen

    Matte

  • Evergreen

    No

  • Showy Bark

    No

Special Characteristics

  • Usage

    Container, Hanging Basket, Houseplant, Tropical

  • Sharp or Has Thorns

    No

  • Invasive

    No