Large self-heal

Questions about large self-heal

Does large self-heal need sun or shade?

Large self-heal grows in full sun (6 or more hours of direct sun a day), part sun (4 to 6 hours of sun, including some afternoon sun) and part shade (2 to 4 hours of sun, mostly in the morning).

It wants soil that stays evenly moist, of average fertility, and a good soak in dry spells.

What zones does large self-heal grow in?

USDA zones 5 to 8. It is hardy to zone 5, which means it survives winter nights down to about −10 °F (−23 °C).

Above zone 8 it struggles: the zones measure winter cold, but a plant's top zone usually means the summers are too hot or the winters too mild for it to rest.

Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.

When does large self-heal flower in my zone?

In zone 5 it flowers mid June to early August. As a summer flower it moves about half a week for every zone: earlier where it is warmer.

Worked out from Hopkins' bioclimatic law: spring arrives about four days later for each degree of latitude north, and one zone is roughly two degrees. A warm spring or a cold one moves any garden two weeks either way.

How far apart should large self-heal be planted?

14 in (35 cm) apart, from the middle of one plant to the middle of the next. That is a little closer than its full width of 18 in (45 cm), so a group knits into one patch.

It grows 8 in (20 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.

How many large self-heal plants do I need?

At 14 in apart, set out in staggered rows:

• 9 to fill 10 square feet (about 1 m²)
• 9 for a single row 10 ft (3 m) long
• 28 to fill a 4 × 8 ft bed on its own

In a mixed border, plant it as threes and fives, along the front and just behind it.

In the bed above, the planner used 10 in three groups.

Is there a native plant like large self-heal?

Large self-heal is not native to North America. These North American natives come closest to doing its job:

• Woodland strawberry: the same job in a bed and the same size; flowers early May to late August, white, not purple.
• Creeping woodland phlox: the same job in a bed and the same size; flowers late April to late May, blue, pink or lavender, not purple.
• Green-and-gold: the same job in a bed and the same size; flowers late April to mid June, yellow, not purple.

Matched the way the planner's Swap button matches plants: the same job in a bed, then size, then flowering time.

Will large self-heal spread?

It spreads sideways, by runners or roots; the risk of it taking over is moderate. Spreads by rooting stems and seed. Cut off the spent spikes to limit seedlings.

What flowers after large self-heal?

Large self-heal is over by early August. These start as it finishes and carry the same spot on, so it never goes flat:

• Lilyturf: from early August to mid September, 16 in tall.
• Japanese anemone: from mid August to early October, 3 ft tall.
• Hosta 'Guacamole': from early August to late August, 24 in tall.

What does large self-heal look like in winter?

Large self-heal holds some of its leaves into winter, more in a mild year or a sheltered spot, and they look tired by March. Cut the old ones off as new growth starts.