Thalictrum dioicum

Early Meadowrue

Flora, fauna, earth, and sky...
The natural history of the northwoods

Name:

• Thalictrum, from the Greek, qaliktron (thaliktron), name for the European meadowrue Thalictrum minus.
• dioicum, from the Latin di, "between", and the Greek oikon (oikon), "house", literally, "between two houses"; dioecious.
• Common Name from the habitat of some Thalictrum (though not necessarily this one) and rue, from the Anglo-Saxon rúde, and the Peloponnesian Greek `ruth (hrute), a name originally given to Ruta graveolens and later applied to a host of plants with bitter leaves.
• Other common names include Quicksilver Weed, Dioecious Meadowrue, pigamon dioïque (Qué)

Taxonomy:

• Kingdom Plantae, the Plants
  • Division Magnoliophyta, the Angiosperms (flowering plants)
    • Class Magnoliopsida, the Dicotyledons
    • Subclass Magnoliidae
      • Order Ranunculales, the Buttercups
        • Family Ranunculaceae, the Buttercups, with Actaea, the Baneberries, Clematis, Coptis (Gold Thread), Delphinium (Larkspurs), Hepatica, Ranunculus (Buttercups), and Thalictrum (Meadow Rues).
          • Genus Thalictrum, the Meadowrues; about 100 species of perennial herbaceous plants, from the North Temperate Zone, South America, and Africa.
• Taxonomic Serial Number: 18669

Description:

• A dioecious perennial.
• Leaves alternate and compound, each made up of many small, round, scalloped leaflets; on long stalks.
• Stem erect, hollow, 8"-30", from a rootstock, that bears dried persistent bracts from the growth of previous seasons.
• Roots yellow to light brown and fibrous, from stout rootstalk.
• Flowers feathery, both male and female; in drooping bunches
  • Sepals 4, purple to greenish-white; dropping off before fruits are formed
  • Petals absent
  • Stamens tiny and threadlike, less than ¼" long, extending like tassels from the sepals.
• Fruit an achene with no particular dispersal mechanism. Dry fruits drop near the parent plant unless consumed.

Identification:

Distribution:

• Ontario to Maine, south to the eastern Dakotas, Minnesota, Iowa, Missouri, Tennessee and the southern Appalachians.

Habitat:

• Aluvial soils that range from well-drained sandy loams to poorly drained clays; however, it usually is found on well-drained soils.
• Moist open woods and on north-facing slopes, ledges, rocky areas, ravines, and near limestone outcrops.
• Shade tolerant; occurs as a minor component (up to 25% cover) in subclimax communities of Bur Oak (Quercus macrocarpa) and Quaking Aspen (Populus tremuloides).

Fire:

• Fire severity and rooting depth of the caudex control recovery. With shallow rooted caudex, the degree of resistance to fire depends on protection obtained from soil cover. Is most likely to survive cool fires that do not consume duff . However, seedlings probably will not survive.
• Probably top-killed by fire. Abundance would be severely reduced immediately postfire, but because it reproduces both vegetatively and sexually, long-term recovery should be fairly successful.
• Off-site regeneration is possible but likely slow, since seed is not wind dispersed.

Associates:

• Trees: Quaking Aspen (Populus tremuloides), Bur Oak (Quercus macrocarpa)

History:

Uses:

Reproduction:

• Has a shallowly rooted caudex. Foliage dies back to this rootstock each winter and resprouts in spring. Generally grows in colonies.
• Blooms in early spring (April or May), when its leaves are barely half grown and with or before the expansion of leaves on deciduous trees. Fruit begins to mature about a month later.

Propagation:

• By seed, following cold stratification, but usually requires two years to bloom.
• By division. After flowering, the fibrous root structure produces offshoots at the base of the plant that become new plants the following season; these can be cut away to establish new plantings. Plant root clumps in the spring or fall, spacing them 1'-2' apart, with the base of the plant at soil level. Mulch to keep the soil moist.

Cultivation:

• Hardy to USDA Zone 3 (average minimum annual temperature -40ºF)
• Cultural Requirements
• shade to part shade
• well-drained, slightly acidic (pH 6-7), organic garden soil
• Grown primarily for its grey green, fernlike foliage. It persists in dry summer and autumn and provides good ground cover for shaded wildflower gardens.
• Flowers April/May
• Cultivars and species available by mail order from specialty suppliers or at local nurseries

Links:

• Fire Effects Information System (FEIS)

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