Growing Persicaria (Bisort, Knotweed)

Latin Name Pronunciation: per-si-kar'-ee-ah

Members of this genus are sometimes included in Polygonum (known to many gardeners through the unwelcome guest called Knotweed). Upwards of 50 species of annuals and perennials grow in a range of conditions worldwide. The ornamental, noninvasive species add carefree late summer color and range in size from low mats suitable for rock gardens to tall, back-of-the border specimens.

Light/Watering: Full sun or partial shade; moist soil is needed for good flowering.

Fertilizer/Soil and pH: Any moist soil is acceptable. We do not recommend fertilizing at planting time or during the first growing season.

Pests/Diseases: Usually trouble-free; slugs may be a problem.

Dividing/Transplanting: Divide large clumps in spring; plant crowns at soil level.

End-of-Season Care: Cut down and remove top growth. After the ground freezes, protect plants during their first winter with a 4-6in layer of oak leaves, pine boughs, or straw.

Calendar of Care -- Persicaria

Early Spring: Gradually remove winter cover.

Fall: Cut back to remove spent flower heads.

Email Sign Up

Subscribe to enjoy gardening advice, email offers & more