Growing Purple Knight Alternanthera Garden Seeds
- Taxonomy: Alternanthera dentata
- Other Names: Joseph’s Coat, Joyweeds
- Seed Type: Annual (Perennial to Zones 10 – 11)
- Sow Indoors or Outdoors: Purple Knight Alternanthera is easy to grow from seed and most commonly sown directly outdoors after the frost but, for earliest blooms, start seeds indoors 6 – 8 weeks prior. Alternanthera decorative foliage seeds will germinate in 5 – 14 days with full lighting and harden off plants to a sunny place in the garden to promote maximum color. Plants are popularly repotted overwinter.
- Days to Maturity: 70 – 77 days
- Hardiness Zone: 7 – 11
- Seed Planting Depth: Lightly press without covering 3 – 4 seeds into soil
- Plant Spacing: 18 – 36”
- Growth Habit: 18 – 24” tall mounding shrub with an 18 – 36” spread of dense leafy ground cover
- Soil Preference: Organically rich, consistently moist, well-drained
- Light Preference: Full sun – Partial shade
- Diseases/Pests/Troubleshooting: Purple Knight Alternanthera requires consistently moist soil and must not be allowed to dry out or foliage and color will suffer. Plants will show signs of wilt if left un-shaded during excessive summer heat. Alternanthera plants have no serious pests or diseases but monitor regularly for aphids and spider mites. Plants will shoot small white blooms in the summer, however, most gardeners prefer to pinch the shoots to focus energies on the vibrant leaf production instead.
- Plant Leaf Color: Deep shades of purple and red ground cover
Alternanthera dentata, or otherwise best known as Purple Knight, Joyweed or Joseph’s Coat, is one of the most prominent and easily recognizable ground covers in the world. Most species of Alternanthera are used as ornamentals, while some species are grown as a vegetable in various parts of Asia. There is a variety of similarly dark leafy grows that can often be substituted or grown in tandem with Purple Knight alternanthera including dichondra, iresine, and plectranthus.