Spike speedwell

Questions about spike speedwell

Does spike speedwell need sun or shade?

Spike speedwell grows in full sun (6 or more hours of direct sun a day).

It wants ordinary well-drained soil, of average fertility, and little watering once settled.

What zones does spike speedwell grow in?

USDA zones 3 to 8. It is hardy to zone 3, which means it survives winter nights down to about −30 °F (−34 °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 spike speedwell flower in my zone?

In zone 5 it flowers late 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 spike speedwell be planted?

16 in (40 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 18 in (45 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.

How many spike speedwell plants do I need?

At 16 in apart, set out in staggered rows:

• 7 to fill 10 square feet (about 1 m²)
• 8 for a single row 10 ft (3 m) long
• 21 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 one in one group.

Is spike speedwell poisonous to dogs and cats?

No toxicity is recorded for dogs, cats, horses or people, according to NC State Extension.

"Not toxic" is not "edible": a pet that eats a lot of any plant can be sick.

Is there a native plant like spike speedwell?

Spike speedwell comes from Europe and Asia. These North American natives come closest to doing its job:

• Stokes' aster: the same job in a bed, the same size, the same flowering time and the same colour.
• Sundrops 'Fireworks': the same job in a bed and the same size; flowers early June to mid July, yellow, not blue.

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

Do deer eat spike speedwell?

Mostly not. NC State lists it as resistant to deer and rabbits. No plant is proof against a hungry deer in a hard winter, but this one is low on the menu.

What flowers after spike speedwell?

Spike speedwell 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.
• Sedum 'Autumn Joy': from mid August to mid October, 24 in tall.
• Little bluestem 'Standing Ovation': from early August to mid September, 3½ ft tall.

What does spike speedwell look like in winter?

Spike speedwell 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.

Is spike speedwell good for bees and butterflies?

Spike speedwell is visited by bees and butterflies.