The Best Perennial Plants for Flower Boxes

Flower boxes are a great way to add color and texture to patios, porches, railings, and windows. While annuals are commonly used in flower boxes, perennials can provide lasting beauty year after year. When selecting perennials for flower boxes, consider bloom time, height, and growing conditions. Read on for tips on choosing the best perennials for your flower boxes.

Key Considerations for Perennials in Flower Boxes

When selecting perennials for flower boxes, keep these key factors in mind:

• Bloom time – Choose a variety of perennials with different bloom times for non-stop color Early bloomers like hellebores and heuchera are followed by salvias, monarda, and daylilies in summer. Late bloomers like asters and mums extend the show into fall

• Height and habit – Look for short mounding perennials or trailing varieties that won’t outgrow the flower box. Tall plants like delphinium may need staking.

• Sun exposure – Match the perennial to the light levels. Full sun lovers like sedum and lavender need at least 6 hours of direct sun. Hostas, coral bells, and ferns prefer part shade.

• Soil and drainage – Good drainage is crucial, so ensure the flower box and soil mix drain well. Amend soil with compost to improve moisture retention.

• Overwintering – In cold climates, protect flower boxes or move pots to an unheated area like a garage. Mulch tender perennials for insulation.

Top Perennial Plants for Flower Boxes

Here are some of the best perennials to grow in flower boxes:

Spring Bloomers

• Hellebores – Also called Lenten roses, they produce rose-like blooms in white, pinks, purples and more in late winter and early spring. Cut back old foliage in fall to showcase the flowers.

• Heuchera – Coral bells offer evergreen foliage in hues like lime green, deep red and bronze. The newer hybrids have amazing leaf colors. Bloom stalks appear in spring.

• Ajuga – Carpet bugleweed is a fast spreading perennial with pretty blue flower spikes in spring above dark green, purple or variegated leaves.

• Alyssum – A short trailing plant that blooms profusely with clusters of tiny fragrant white or purple flowers in spring. Repeats bloom in fall.

• Arabis – One of the earliest bloomers, this forms a mat of gray-green leaves with masses of small white flowers in early spring.

Summer Bloomers

• Lavender – Fragrant gray-green foliage and abundant purple flower spikes that attract pollinators. Opt for compact varieties like ‘Munstead’ or ‘Hidcote’.

• Catmint – Nepeta has aromatic gray-green leaves and airy displays of purple flowers summer through fall. It’s drought tolerant once established.

• Salvia – This diverse plant genus offers spikes of tubular flowers in shades of red, pink, purple and white beginning in early summer. Many are long blooming.

• Veronica – Speedwell offers upright flower spikes in blue, purple and pink hues. Look for compact types like ‘Sunny Border Blue’. Remove spent blooms to encourage reblooming.

• Daylily – Each flower of daylily only lasts a day but they bloom in succession all season in colors like apricot, yellow, pink and red. Divide clumps every few years.

Late Season Bloomers

• Sedum – Succulent leaves in gray, green and purple hues. Blooms appear in late summer and fall in shades of pink, red and white. Cut back in early spring.

• Aster – Daisy-like blooms in purple, pink and white bloom prolifically on compact mounding plants from late summer to fall. Deadhead spent flowers.

• Chrysanthemum – Florist grade mums offer bursts of color in fall with blooms in yellow, coral, red and more. Provide good drainage and consistent water.

• Ornamental grasses – Add texture and movement with grasses like dwarf fountain grass, blue oat grass and Japanese forest grass. Most grasses bloom in fall.

Designing with Perennials in Flower Boxes

When planting perennials in flower boxes, combine early, mid and late season bloomers for non-stop color. Also mix heights, textures, and colors for visual interest. Here are some tips:

• Plant sun-lovers like catmint, lavender and sedum together for a hot, dry area. Add annuals like marigolds, zinnias or petunias for pops of color.

• Hostas, ferns, coral bells and hellebores combine nicely for a shady flower box. Add impatiens or begonias as annuals.

• Try a patriotic theme with red salvia, white alyssum and blue creeping phlox.

• Mix it up with yellow coreopsis, purple asters and trailing blue lobelia.

• Go for all white with varieties of alyssum, Shasta daisies and white lavender like ‘Alba’.

• Plant a fragrant flower box with lavender, mint, thyme, and alyssum.

With the right selection and care, perennials can provide lasting beauty in flower boxes year after year. Give them a try for rewarding, low maintenance flower boxes!