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Manitoba Museum

Madder (Rubiaceae)

Long-leaved Bluets

Houstonia longifolia Gaertn.

This delicate-looking spring perennial plant produces clusters of small tube-shaped flowers that are mainly pollinated by small bees and day-flying moths. There are two different flower forms. Some have long fertile styles with shorter non-fertile stamens, and others have long fertile stamens with shorter non-fertile styles. For pollination to be effective, insects must visit both flower types.

Flower Colour:

  • White

Flowering Season:

  • Spring
  • Summer
  • Fall

Flowering Months:

  • August
  • July
  • June
  • May
  • September

Canadian Rarity Status:

Not rare. Listed as “may be at risk” in Alberta and Quebec.

Physical Appearance:

Plants have several branching, 4-sided stems that grow 9-25 cm tall. A rosette of basal leaves withers before flowers bloom. The stem leaves are opposite and linear to lance-shaped, with smooth edges and one vein. Flowers are arranged in small flat-headed clusters. Each tube-shaped flower has four spreading lobes, a hairy throat, and a green calyx with four teeth. Fruits are capsules that split open at the top to release several small black seeds.

Similar Species:

Pale Comandra, Northern Bedstraw, Sea Milkwort (Glaux maritima L.)

Gardening Notes:

Seeds and/or plants may be available from greenhouses and seed supply companies specializing in native plants. Plants are easy to cultivate and adapt well to rock gardens.

Canadian Distribution:

  • Alberta
  • Manitoba
  • Ontario
  • Quebec
  • Saskatchewan

Prairie Types:

  • Fescue Prairie
  • Tall Grass Prairie


  • Dunes
  • Forests
  • Prairies
  • Rocky Outcrops

Moisture Conditions:

  • Dry

Light Preference:

  • Full Sun
  • Part Shade

Soil Preference:

  • Gravel
  • Sand
Long-leaved Bluets