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Archives: Plant Answer Line Q & A

Plant Answer Line questions and answers.

encouraging flower growth on gooseneck loosestrife

I was very excited to plant some gooseneck loosestrife in my garden but it has proven to be a dismal failure. It’s been three years and the plant is refusing to “gooseneck”. Instead, it gives me very frail flowers, reaching straight up and lasting a very short time. I’m at the point of pulling it all out, but wanted to see if there was any way to encourage it to offer up some healthy, bobbing white flowers.

What are the conditions where the gooseneck loosestrife (Lysimachia clethroides) is planted? This plant tolerates
partial shade to full sun. The fact that yours is growing straight up makes me wonder if it is in too much shade and is striving for more light. Usually, this is a vigorous plant (sometimes exceedingly so–it can become invasive), so other things to consider are soil conditions (prefers well-drained soil with a lot of organic matter), and moisture. If planted in full sun, loosestrife will need sufficient water to thrive.

It is possible, too, that after 3 years, your plant needs to be dug up and divided. This might help give it renewed vigor. Propagation information from the Iowa State University Extension suggests that “Perennials such as gooseneck loosestrife (Lysimachia clethroides)… may be divided every 3-5 years to improve plant health.”

Other good sources of information about this plant are Cornell, and the Kemper Center for Home Gardening.

more about Lysimachia punctata ‘Alexander’

I bought a Lysimachia punctata ‘Alexander’ (variegated) at a plant sale last weekend. I can’t find anything about it in my books. Can you tell me more about it? How tall, invasive or not, best place to plant, anything else you think I should know.

 

I found information on the website of a local gardener, Paghat, with a detailed description of this form of loosestrife. Although it is not supposed to be as aggressive as the species (L. punctata) or as invasive as L. vulgaris (a noxious weed in King County), I recommend keeping an eye on it. Paghat says:
“‘Alexander’ has variegated leaves, sage-green with cream borders, and sunny yellow flowers. It purports to be a more restrained version of a flower that in the species form is notoriously invasive and often too aggressive for neighboring perennials. Even ‘Alexander,’ though comparatively slow growing, eventually becomes a large two-foot by two-foot clump with a big root system that can threaten nearby delicate flowers, so take care what you plant around it.”