Comfrey or Symphytum is one of the most underused perennial flowers available for the shade garden. My two cents is that I really like the variegated forms of this plant and they belong in my garden. Never mind trying to grow these plants in full hot sunshine – follow the directions below for success.
Where to Grow
Growing Symphytum is easiest when you treat it like a perennial Brunnera. Plant it in the part shade in a damp soil. Or if not a damp soil, a soil rich in organic matter (a deep woodland soil)
If you grow it in the full sunshine, it will thrive in excellent soils that are well watered but will not do well in soils that are well-drained and sandy (dry soils). You’ll also likely find the coloring will be poor and it will be short-lived but that would be your choice.
Symphytum species plants will self-sow like crazy when they are happy and indeed can be a nuisance weed. Given this is a self sower and not an underground rhizome plant, it can be controlled with a sharp hoe.
Seed is relatively easily started. Give it 90 days in the refrigerator crisper at 40F and then plant in soil keeping the soil temperature at 70F.
Barely cover the seed.
A January sowing should produce good seedlings for May planting-out .
This is an excellent plant for the shady garden. The green-gold foliage combinations are excellent and when combined with heavy flowering (although the flowers are small) it makes an excellent ornamental plant.
It can be a large plant so gardeners should pick varieties appropriate to the size of the garden.
Varieties and Use
- S. officinalis is the comfrey of medicinal use (23-30 inches tall and heavily self-sowing). It is also used as a green manure and dug under in the fall. The leaves of this species are high in almost all nutrients and makes an excellent compost or liquid tea for containers and potted plants.
- S. uplandica is the parent plant in modern breeding. Remove the flowers to increase the bulk of the leaves and the leaf coloring.
These are some of the commonly available plants and I include these with the note that nurseries are now introducing more hybrids on a yearly basis. Grow these for their foliage and their flowers.
- ‘Axminster Gold’ is 18-24 inches tall with gold tones to the leaves
- ‘Goldsmith’ is 12 inches tall, dark green foliage edged with cream.
- ‘Hidcote Blue’ spreader to 18 inches tall flowers are soft blue and white
- ‘Langthorn’s Pink’ is a 5 foot tall plant with many pink flowers
- ‘Rubrum’ to 12 inches tall, flowers are a mid-red.