Yellow loosestrife

Questions about yellow loosestrife

Does yellow loosestrife need sun or shade?

Yellow loosestrife 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. It copes with soil that stays wet.

What zones does yellow loosestrife grow in?

USDA zones 4 to 8. It is hardy to zone 4, which means it survives winter nights down to about −20 °F (−29 °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 yellow loosestrife flower in my zone?

In zone 5 it flowers mid 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 yellow loosestrife be planted?

18 in (45 cm) apart, from the middle of one plant to the middle of the next. That is a little closer than its full width of 24 in (60 cm), so a group knits into one patch.

It grows 3 ft (90 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.

How many yellow loosestrife 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 yellow loosestrife 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 yellow loosestrife?

Yellow loosestrife comes from Eastern Central & South Eastern Europe to Northern Iran, Asia. These North American natives come closest to doing its job:

• Golden Alexanders: the same job in a bed and the same colour; 8 in shorter, flowers early May to mid June.
• Bee balm 'Purple Rooster': the same job in a bed and the same size; flowers late June to mid August, purple, not yellow.
• Indian pink: the same job in a bed; 16 in shorter, flowers early June to early July.

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

Do deer eat yellow loosestrife?

They may. NC State does not list it as resistant to deer or rabbits. Where they visit, protect it, or plant it among ones they avoid.

Will yellow loosestrife spread?

It spreads sideways, by runners or roots; the risk of it taking over is high. Spreads aggressively by underground runners in moist soil and has escaped from gardens in the Northeast and Northwest. Contain it or plant it where it can do no harm.

What flowers after yellow loosestrife?

Yellow loosestrife is over by late July. These start as it finishes and carry the same spot on, so it never goes flat:

• Joe Pye weed 'Gateway': from late July to mid September, 6 ft tall (a recorded partner).
• Japanese anemone: from mid August to early October, 3 ft tall.
• Lilyturf: from early August to mid September, 16 in tall, to stand in front of it and cover its fading stems.

What does yellow loosestrife look like in winter?

Yellow loosestrife 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 yellow loosestrife good for bees and butterflies?

Yellow loosestrife is visited by pollinators, specialist bees and butterflies.