Masterwort

Questions about masterwort

Does masterwort need sun or shade?

Masterwort grows in 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, rich in organic matter, and a good soak in dry spells.

What zones does masterwort grow in?

USDA zones 4 to 7. It is hardy to zone 4, which means it survives winter nights down to about −20 °F (−29 °C).

Above zone 7 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 masterwort flower in my zone?

In zone 5 it flowers early June to late July. 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 masterwort be planted?

18 in (45 cm) apart, from the middle of one plant to the middle of the next. That is about its full width, so each plant keeps its own outline.

It grows 24 in (60 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.

How many masterwort plants do I need?

At 18 in apart, set out in staggered rows:

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

In a mixed border, plant it as a group of three or five, with a second group further along in the other number.

In the bed above, the planner used three in one group.

Is there a native plant like masterwort?

Masterwort is not native to North America. These North American natives come closest to doing its job:

• Indian pink: the same job in a bed; 4 in shorter, flowers early June to early July.
• Garden phlox 'Bright Eyes': the same job in a bed and the same colour; 8 in taller, flowers mid July to late August.

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

What flowers after masterwort?

Masterwort is over by late July. 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, to stand in front of it and cover its fading stems.
• Japanese anemone: from mid August to early October, 3 ft tall.
• Garden phlox: from mid July to early September, 3½ ft tall.

What does masterwort look like in winter?

Masterwort dies down to the ground and there is nothing to see until spring. The old stems can be cut in autumn, or left until spring as shelter for overwintering insects.