What are the best perennials for window boxes?
Written by
Benjamin Miller
Reviewed by
Prof. Martin Thorne, Ph.D.Perennial window box plants give you consistent beauty season after season with the right care. Heuchera gives you beautiful foliage colors. Ajuga acts as a dense groundcover. Carex grasses act as the texture. Hostas love the shade. These hardy plants create a lasting display that actually gets better as time goes on.
Foliage Stars
- Heuchera: Vibrant leaves in purple, silver, and lime shades
- Hostas: Large textured leaves perfect for shade boxes
- Ajuga: Bronze-purple foliage spreading attractively
Textural Elements
- Carex grass: Fine blades offering movement and softness
- Liriope: Strappy leaves with seasonal flower spikes
- Ferns: Delicate fronds creating feathery effects
Compact Bloomers
- Dwarf asters: Fall flowers attracting pollinators
- Creeping phlox: Spring blooms covering surfaces densely
- Miniature daylilies: Summer color on compact plants
Create perennial combinations with the boiler-filler-chiller approach. Tall upright heuchera behind mounding hostas with cascading ajuga. Combine foliage colors like silver carex with purple heuchera. Additionally, consider incorporating seasonal bloomers, such as phlox, for a momentary colored accent within the otherwise permanent foliage plants.
By preparing correctly, you can ensure perennial longevity. Plant in a deep box (at least 10 inches) for optimal root development. Use soil that drains water well and extra perlite in the soil mix. Space plants adequately to allow for mature growth. Water deeply after planting to promote root systems in your plants.
Winter protection helps keep perennials healthy in cold-winter hardiness zones. Insulate roots with 3 inches of mulch after the first frost. During severe freezes, wrap boxes in burlap to protect them from damage. Water monthly when thawing occurs and the temperature is above 40°F. Prune dead foliage back only in the spring when the frost-free period has passed.
Routine seasonal care practices encourage active growth. Use a balanced fertilizer around early spring. Deadhead flowering varieties as the flowers fade. Divide clumps of crowded plants once every 2 to 3 years. At the start of each growing season, refresh and replenish the topsoil to replenish nutrients absorbed during the previous season.
Read the full article: Ultimate Guide to Window Box Plants
