Plant Guide

Trachelium caeruleum

thoatwort, blue throatwort

Herbaceous perennial originating from the Mediterranean region with toothed, oval leaves, and small purple, slightly scented flowers in domed clusters (8-15 cm wide) during summer. The common name alludes to the fact that the plant was thought to have medicinal powers and used as a gargle for sore throats.

Prefers a sunny position in any well-draining, fertile soil. Although Trachelium caeruleum prefers an average supply of moisture, it can handle quite dry conditions. Cut back after flowering. Self-seeds readily and flowers in its first year from seed. Usually pest and disease free. Lasts for about 2 weeks as a cut flower. Flowers are ready for picking when 1/4 to 1/3 of the florets are open. Tolerates light-medium frosts (to about -7 deg Celsius, zones 9-11). Often grown as an annual in colder climates. Suitable for coastal gardens.

In the photo Trachelium caeruleum is growing in a pot together with Agapanthus, resulting in a beautiful colour combination when both are flowering at the same time. Trachelium is also suitable for the flower border, and looks great in combination with either yellow (e.g. dahlias and yarrow) or red flowering plants (e.g. Rosa 'Flowercarpet red'). Great for bees and butterflies!

Type of plant

Herbaceous - Perennial

Size

to about 1 m tall by .5 m wide

Landscape Use

flower display in cottage, informal or Mediterranean-style gardens, container plant, cut flower

Specifications

  • Temperature: Half hardy
  • Light: High
  • Moisture: Medium
  • Soil: Light Medium Heavy
  • Wind tolerance: Average
  • Coastal tolerance: High