Description Of Commercially Available Species
D. bulbosa Rosetted plants that occur in two forms. "Hill" form: Leaves become maroon to purplish upon maturity attaining lengths of 2.5 in. (6 cm). Petiole is wedge-shaped with a round blade. White flowers are borne singly on each of several scapes. The orange tuber is heart-shaped with scales.
"Sand" form: Similar to the "Hill" form but is smaller, having fewer leaves. The tuber is spherical lacking scales and may be white, pink, or red.
D. erythrorhiza A rosetted plant with a circular blade tapering toward the base to a short almost indistinguishable petiole. Blade is about 1.2 in. (3 cm) wide. Numerous white flowers are borne on a single scape. There are 2 forms in this species. The tubers of both forms are red with scales.
"Sand" form: Usually has up to 6 leaves whose blades are not as circular as those of the "Hill" form. "Hill" form: This variety is more robust with plants usually having more leaves than the "Sand" form.
- gigantea An erect plant with numerous branches. It can exceed a height of 40 in. (102 cm). Color varies from yellowish green to maroon. The cupped, peltate leaves have upward pointed lobes. Smaller leaves develop later in the season from the leaf axils. Scale-like leaves occur on the lower portion of the stem. Numerous white flowers are terminal on the branches. The red kidney-shaped tuber has scales. (Photo 4-6) When this plant emerges from the soil in the fall it resembles an asparagus shoot.
- heterophylla An erect plant growing up to 14 in. (36 cm) high. Leaves are shield-to almost kidney-shaped on short petioles with the blade about 0.2 in. (5 mm) long, occurring singly on the upper part of the stem. Scale-like leaves occur on the lower part of the stem. One or more white or pink flowers are borne on the top of the foliage stem.
- huegelii An erect plant whose stem zigzags to a length of 29 in. (74 cm) or more with usually fewer than 8 leaves and at times may have only scale-like leaves. The upper leaves, hanging from long petioles, are round and cupped about 0.4 in. (1 cm) wide with the tentacled surface facing downward. The leaves on the lower part of the stem are of the scale type. Numerous white to pink flowers are borne terminally on the foliage stems. The tubers are white.
- macrantha Leaves and stem are yellowish green and have no red coloration. The climbing stem can reach a length of 51 in. (130 cm) and its leaf blades are round, cupped and up to 0.4 in. (1 cm) in diameter. Leaves are arranged in groups of 3 on the stem with 1 of the leaves having a much longer petiole than the others. Scale-like leaves occur on the lower part of the stem. Several white or pink flowers are borne on the top of the foliage stem. The tuber is white and usually kidney-shaped with a bumpy surface.
- macrophylla A rosetted plant with a roundish blade tapering to a short petiole. Leaves are up to 2.4 in. (6 cm) across at the widest point and up to 4.8 in. (12 cm) long. Leaves do riot develop a red coloration. Usually 2 or more white flowers with black spotted sepals are borne on each of several scapes. The tuber is orange-red.
- menziesii There are several varieties of this species which can be erect or climbing or have a stem that zigzags, reaching a length of 40 in. (102 cm) or more. Color ranges from red to purple. Leaves are round and cupped and up to 0.2 in. (5 mm) in diameter. They occur in groups of 3 with 1 leaf having a much longer petiole than the other 2. Several red to pink flowers are borne terminally on the foliage stem. The tuber is pink.
- modesta A yellowish green climbing plant that can exceed 40 in. (102 cm) in length. Leaves are cupped and shield-shaped with 2 upward pointed lobes and are about 0.2 in. (5 mm) wide. The 2-lobe leaf distinguishes this plant from D. macrantha. Leaves occur in groups of 3 with 1 leaf having a much longer petiole than the other 2. Scale-like leaves occur on the bottom part of the foliage stem. Numerous white flowers are borne on the end of the foliage stem. The tubers are white.
- platypoda Erect plant with a skimpy basal rosette of leaves. Leaves are fan-shaped and may tend to become funnel-shaped. This plant can be easily distinguished from D. stolonifera which usually has the same shaped leaves in that the leaves are borne singly in the former and in whorls of 3-4 in the latter. Leaves may be up to 0.2 in. (5 mm) across the widest part and 0.6 in. (1.5 cm) long. Numerous white flowers, with black spotted sepals, are borne on a simple or branched stem terminally on the foliage stem or on a scape arising from the basal rosette. The orange tuber is oval-shaped with scales and is pointed on the bottom.
- ramellosa The plant consists of a basal rosette of leaves and one or more erect stems. The clasping, fan-shaped yellowish green leaves are alternately arranged on the stem. From 1 to several white flowers are borne on each short scape which can number from 1 to several. The tuber is orange-red.
- stolonifera There are several forms that vary from a single erect stem with a basal rosette of leaves to branching forms which may have several semi-erect stems. Leaves are usually fan-shaped with size varying considerably in the various forms. Leaves may be red, purple or orange and occur in whorls of 3 to 4. White flowers are borne on a branching scape and in some forms on the top of the foliage stem. The red tuber has scales and the upper surface is concave. In cross section it is kidney-shaped.
- sulphurea A greenish, erect plant with a zigzag stem that can be up to 18 in. (46 cm) long. Leaves occur in groups of 3 with 1 leaf on a much longer petiole than the other 2. They are shield-shaped with 2 pointed lobes about 0.2 in. (5 mm) wide. Scale-like leaves clothe the lower part of the stem. Several bright yellow flowers are borne on the top of the foliage stem. Tuber color is yellow or pink to white.
- zonaria A rosetted plant with green, kidney-shaped leaves. The leaf blade is up to 0.6 in. (1.5 cm) wide. The petioles are covered by the overlapping blades. Leaf margins tend to become red to maroon. Numerous white flowers are borne on a single scape. Tubers are red with scales and tend to be spherical.
CULTURAL INFORMATION Planting Media
Media pH should be in the range of 4.5 to 6.5. For the "well-drained" species 2 parts sand to 1 part sphagnum peat moss. For the "poorly-drained" and "damp medium" species: 2 parts sphagnum peat moss and 1 part sand. Media should be at least 5 in. (13 cm) deep, but preferably 10 in. (25 cm) or more. We have successfully grown D. gigantea in a 2 ft. (0.6 m) length of 6 in. drain tile. (Note, tubers of D. gigantea can be 5 ft. (1.5 m) deep in nature.) Tubers should be planted a minimum of 2 in. (5 cm) below the medium surface in shallow pots [5 in. (13 cm)] and down to Vz the depth of the soil in deeper pots [10 in. (25 cm)]. The crown of the tuber, the end with an indentation in which the 'eye' is found, must be oriented to the surface of the medium.
During the growing season 40-79°F (4-26°C). Dormant season 70-100°F (21-38°C).
All of the tuberous Drosera, with a few exceptions, require a dormant period in the summer of about 5 months. (Drosera whittakeri, is the exception to the rule. It is an alpine plant which grows during the summer and is dormant during the winter.) We have grown D. peltata and D. auriculata for 15 years in wet soils the year around. They grow, flower, produce seed and die back each year. Our plants grow during the latter part of the winter and into the summer. These 2 species will also grow with a wet and dry season just as well as they do with wet soils the year around. Despite our experience with these 2 species it is best to follow the rule that dormancy is critical for most tuberous Drosera species.
Dormancy is presumably initiated by the flowering process. Usually, during flowering, new tubers are formed so that by the end of the flowering period they have developed fully. After flowering, when the plants start to turn yellow and die, allow the soil to dry out slowly by taking the pots out of trays of water if they are maintained this way and/or by withholding water. Once the medium is dry, place the plants out of the sun's direct rays and do not water. Some growers give the plants water once or twice during the dormant period to simulate the rain they get during the summer from infrequent thundershowers in their native environment. Some growers remove the tubers from the soil once they are dormant and place them in plastic bags for storage at room temperature, 68-86°F (20-30°C). It has been reported that this procedure stimulates flowering.
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