Hosta Sum and Substance

Hosta sieboldiana 

‘Sum and Substance’ Hosta – Care Guide

Overview

Hosta ‘Sum and Substance’ is a giant-sized perennial prized for its bold chartreuse to golden-green leaves, substantial texture, and slug resistance. It forms a dramatic clump that can serve as a focal point in shaded or partially shaded garden beds. This award-winning cultivar is both vigorous and long-lived, making it a staple in many shade gardens across Canada.

Key Characteristics

• Botanical Name: Hosta ‘Sum and Substance’

• Common Name: Sum and Substance Hosta

• Plant Type: Herbaceous perennial

• Hardiness Zones: 3–9

• Mature Height: 24–36 inches (60–90 cm)

• Spread: 48–72 inches (120–180 cm)

• Growth Habit: Large, mounding clump

• Foliage: Thick, gold-chartreuse to lime green heart-shaped leaves that intensify in sun

• Flowers: Pale lavender, funnel-shaped blooms on tall stalks in mid to late summer

• Fragrance: Slightly fragrant blooms (but not a fragrant cultivar)

Sun Requirements

• Prefers part shade to full shade, especially in hot summers

• Can tolerate morning sun or filtered light, which enhances its golden tones

• Too much sun in hot climates can cause leaf scorch — in Zone 3, some sun is beneficial

Watering Needs

• Keep soil evenly moist, especially in hot or dry periods

• Water deeply once or twice a week during dry spells

• Mulch around the base to conserve moisture and regulate soil temperature

Soil Requirements

• Grows best in rich, well-drained soil with high organic matter

• Tolerates clay soil if drainage is adequate

• Amend planting area with compost or aged manure for best growth

Cold Hardiness (Zone 3 Tips)

• Extremely cold-hardy when planted in the ground

• In Zone 3, plant crowns at soil level and mulch well in late fall to protect from freeze-thaw cycles

• Will reliably return in spring once the ground warms

Flowering

• Produces tall scapes (flower stalks) up to 3–4 feet tall with light lavender blooms in July or August

• Blooms attract bees and pollinators

• You can deadhead spent flowers or leave stalks for winter interest

Maintenance

• Remove old foliage in fall or early spring before new shoots appear

• Fertilize in early spring with a slow-release balanced fertilizer or compost

• Divide every 5–7 years in spring or early fall if clump becomes too large or overcrowded

Pests & Disease

• Slug-resistant thanks to thick, waxy leaves

• Watch for:

  • Voles in winter (protect with gravel/mulch)

  • Leaf scorch in full sun or drought

  • Crown rot in poorly drained soils

• Disease is rare if air circulation is good

Uses in the Garden

• Specimen or focal plant in shade gardens

• Foundation plantings under trees or beside buildings

• Paired with ferns, heuchera, astilbe, brunnera, and bleeding heart

• Works well in containers (Zone 3: bury pot in soil or overwinter in cold frame/garage)

Special Notes

• Recipient of the American Hosta Growers Association Hosta of the Year (2004)

• Leaves become more golden with more light and remain lime-green in deeper shade

• Long-lived and low-maintenance, ideal for gardeners who want impact with little effort

Photo from prairiegardens.org