Top 14+ Perennials You Should Always Divide In The Fall For A Healthier Garden

This simple maintenance practice encourages new growth and vigorous blooming.

Summer Phlox, Speedwell, Tickseed, Black-eyed Susan, Agapanthus, Spotted Bellflower, Lamb’s Ear, Cranesbill, Coneflower

Plant division is simply the act of dividing or splitting a single plant into multiple plants. Gardeners divide plants to achieve one of three main goals: rejuvenating old and/or overcrowded plants, producing new plants (propagation), and controlling the size of plants. Not all perennials respond

well to division, so it is important to learn which plants benefit from regular division, the best time to divide different plant species, and how often they should be divided.

Fall is generally the best time to divide perennial plants that flower in the spring or summer months, while fall-blooming perennials should be divided in early spring, when the first shoots start to emerge. Most perennials need to be divided every three to five years, though frequency varies by species. Look for signs indicating a plant needs division. These may include poor or reduced flowering, weak shoot growth, or sparse foliage. Many ornamental grasses develop a hollow or dead area in the center of the plant indicating they need to be divided. Other plants may need to be divided because they have outgrown their allocated space in the garden and are intruding on neighboring plants.

A little bit of preparation ensures plants remain healthy during division and replanting. Thoroughly water plants that you plan on digging a day or two before dividing. If you intend on planting some divisions in another location of the garden, take time to prepare the new planting bed before digging and dividing plants. Keep the roots moist while they are waiting to be planted and water plants well after replanting. Mulch plants to retain soil moisture as roots reestablish.

01 of 14

Summer Phlox

Summer Phlox, Speedwell, Tickseed, Black-eyed Susan, Agapanthus, Spotted Bellflower, Lamb’s Ear, Cranesbill, Coneflower
  • Botanical Name: Phlox paniculata
  • Sun Exposure: Full sun to part shade
  • Soil Type: Medium, well-draining, average fertility
  • Soil pH: Slightly acidic to slightly alkaline (6.0-8.0)
  • USDA Plant Hardiness Zone: 4 to 8 

Flowering in white, pink, purple, blue, and red hues, summer phlox produces fragrant blooms from mid to late summer. Also called garden phlox or tall phlox, summer phlox has a spreading root system that can become crowded out the center of the plant over time. Divide plants every three to four years, separating the plant into clumps with three to five vigorous shoots each. Discard small, weak, or woody portions as well as the central core of the plant.

02 of 14

Speedwell

Summer Phlox, Speedwell, Tickseed, Black-eyed Susan, Agapanthus, Spotted Bellflower, Lamb’s Ear, Cranesbill, Coneflower
  • Botanical Name: Veronica spicata
  • Sun Exposure: Full sun
  • Soil Type: Medium to moist, well-draining
  • Soil pH: Acidic to neutral (5.8-7.5)
  • USDA Hardiness Zones: 3 to 9 

Speedwell plants have a low, spreading habit and relatively shallow fibrous root system. Plants benefit from dividing every three to five years to keep them productive. Replant divisions taken from the outer edge of the plants, as these will be most vigorous. You will be rewarded with lush new growth and ample blooms the following season.

03 of 14

Tickseed

Summer Phlox, Speedwell, Tickseed, Black-eyed Susan, Agapanthus, Spotted Bellflower, Lamb’s Ear, Cranesbill, Coneflower
  • Botanical Name: Coreopsis spp.
  • Sun Exposure: Full sun
  • Soil Type: Average to poor, well-draining
  • Soil pH: Acidic (5.5-6.5)
  • USDA Plant Hardiness Zone: 3 to 9

Tickseed or coreopsis includes numerous species of hardy native wildflowers that blooms spring through summer. Plants have spreading roots that benefit from division every one to three years to maintain plant vigor. When dividing plants, discard the weak central portion of the plant and replant divisions taken from the edges. Some coreopsis species live longer when divided regularly.

04 of 14

Beebalm

Summer Phlox, Speedwell, Tickseed, Black-eyed Susan, Agapanthus, Spotted Bellflower, Lamb’s Ear, Cranesbill, Coneflower
  • Botanical Name: Monarda didyma
  • Sun Exposure: Full sun to part shade
  • Soil Type: Rich, medium to moist
  • Soil pH: Slightly acidic to neutral (6.0-7.2)
  • USDA Hardiness Zones: 4 to 9

Beebalm is a fast-growing native perennial that forms dense clumps of fragrant foliage and vibrant red mid-summer blooms. Divide plants every three to four years to thin clumps, reduce spread, and prevent overcrowding. Division also helps increase air flow within the leaf canopy, helping to combat powdery mildew. Discard the woody central clump of the plant when dividing.

05 of 14

Yarrow

Summer Phlox, Speedwell, Tickseed, Black-eyed Susan, Agapanthus, Spotted Bellflower, Lamb’s Ear, Cranesbill, Coneflower
  • Botanical Name: Achillea spp. and cvs.
  • Sun Exposure: Full sun
  • Soil Type: Dry to medium, well-draining, lean
  • Soil pH: Acidic (5.5-6.8)
  • USDA Hardiness Zones: 3 to 9  

Yarrows are beloved plants for supporting pollinators with their flat-topped flower heads packed with tiny, nectar-rich blooms. Yarrow benefits from division every two to three years, or when you notice the center of the plant beginning to die out. Separate the spreading root system by cutting or pulling it apart into several sections. Discard the central core.

06 of 14

Black-eyed Susan

Summer Phlox, Speedwell, Tickseed, Black-eyed Susan, Agapanthus, Spotted Bellflower, Lamb’s Ear, Cranesbill, Coneflower
  • Botanical Name: Rudbeckia fulgida
  • Sun Exposure: Full sun
  • Soil Type: Rich, dry to medium, well-draining
  • Soil pH: Acidic (5.5-6.8)
  • USDA Hardiness Zones: 3 to 9 

The sunny blooms of black-eyed Susan are a mainstay of the summer garden. These plants produce dense clumps through self-seeding and spreading roots. Divide clumps every three to four years using a spade or pitchfork, separating plants into smaller divisions. Division increases plant vigor and improves airflow through the canopy, which helps fight foliage diseases.

07 of 14

Agapanthus

Summer Phlox, Speedwell, Tickseed, Black-eyed Susan, Agapanthus, Spotted Bellflower, Lamb’s Ear, Cranesbill, Coneflower
  • Botanical Name: Agapanthus hybrid 'MP003'
  • Sun Exposure: Full to part sun
  • Soil Type: Organic, medium moisture, well-draining
  • Soil pH: Slightly acidic (5.5-7.5)
  • USDA Hardiness Zones: 8 to 11 

Agapanthus plants thrive when their roots are crowded, so they do not require frequent division. Plants can be divided for propagation or to invigorate plants every four or five years, or when you notice decreased flowering. Agapanthus roots are fleshy and somewhat brittle. Lift plants carefully after flowering slows in autumn. Separate clumps into portions with at least two to three growing points. Plants can also be divides in spring.

08 of 14

Daylily

Summer Phlox, Speedwell, Tickseed, Black-eyed Susan, Agapanthus, Spotted Bellflower, Lamb’s Ear, Cranesbill, Coneflower
  • Botanical Name: Hemerocallis hybrids
  • Sun Exposure: Full sun to part shade
  • Soil Type: Average, medium moisture, well-draining
  • Soil pH: Slightly Acidic to Neutral (6.0-7.0)
  • USDA Hardiness Zones: 4 to 10 

Daylilies can be divided in late fall or in early spring, before growth resumes. Gardeners commonly divide daylilies to increase stock. Division also promotes heavier blooming. Daylilies produce thick, fleshy roots that have multiple growing points. Divide plants every three to six years, separating the roots into segments that contain three or more shoots. Replant divisions, setting each new plant deep enough that the growing point (where the shoot meets the roots) sits one to two inches below the soil surface.

09 of 14

Astilbe

Summer Phlox, Speedwell, Tickseed, Black-eyed Susan, Agapanthus, Spotted Bellflower, Lamb’s Ear, Cranesbill, Coneflower
  • Botanical Name: Astilbe hybrids
  • Sun Exposure: Partial to full shade
  • Soil Type: Average, medium, well-draining
  • Soil pH: Slightly acidic to neutral (5.8-7.0)
  • USDA Hardiness Zones: 4 to 9 

Astilbe looks gorgeous massed in woodland gardens and other shady spots, but flowering often decreases when plants grow too crowded. Keep your astilbe blooming strong by dividing plants every two to three years or when clumps become overcrowded. You may need a sharp spade or knife to cut the fibrous roots into sections.

10 of 14

Spotted Bellflower

Summer Phlox, Speedwell, Tickseed, Black-eyed Susan, Agapanthus, Spotted Bellflower, Lamb’s Ear, Cranesbill, Coneflower
  • Botanical Name: Campanula punctata
  • Sun Exposure: Full sun to part shade
  • Soil Type: Average, medium, well-draining
  • Soil pH: Slightly acidic to alkaline (6.0-8.0)
  • USDA Hardiness Zones: 5 to 9 

This floriferous clump-forming perennial spreads by rhizome to form large clumps. Plants can be divided in spring or fall every two to three years or when the plants become crowded. Divide plants into clumps with three to five vigorous shoots each, discarding any small, weak, or woody portions.

11 of 14

Hosta

Summer Phlox, Speedwell, Tickseed, Black-eyed Susan, Agapanthus, Spotted Bellflower, Lamb’s Ear, Cranesbill, Coneflower
  • Botanical Name: Hosta spp. and cltvs.
  • Sun Exposure: Partial to full shade; dappled sun
  • Soil Type: Rich, moist, well-draining
  • Soil pH: Slightly acidic to neutral (5.5-6.2)
  • USDA Hardiness Zones: 3 to 9 

Hostas are hardy, low-maintenance plants that seldom require division for performance purposes and plants looks best when they are not divided too often. However, plants can develop sparse centers over time and may benefit from division after six or more years of growth. Gardeners also divide hosta plants to propagate new plants. This can be done by cutting a small section from the edge of the plant, which will quickly refill. If plants require division, cut the fleshy roots into clumps with two to three eyes or growing points.

12 of 14

Lamb’s Ear

Summer Phlox, Speedwell, Tickseed, Black-eyed Susan, Agapanthus, Spotted Bellflower, Lamb’s Ear, Cranesbill, Coneflower
  • Botanical Name: Stachys byzantina
  • Sun Exposure: Full to partial sun
  • Soil Type: Average, dry to medium, well-draining
  • Soil pH: Adaptable (6.0-8.0)
  • USDA Hardiness Zones: 4 to 9 

This velvety groundcover spreads by creeping stems to form dense clumps. Plants can grow aggressively under optimal conditions. Divide plants every two to four years to manage spread and propagate new plants. Discard the weak central portion of the plant. Set divisions twelve to eighteen inches apart to allow plenty of room for the new plants to spread.

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Cranesbill

Summer Phlox, Speedwell, Tickseed, Black-eyed Susan, Agapanthus, Spotted Bellflower, Lamb’s Ear, Cranesbill, Coneflower
  • Botanical Name: Geranium spp.
  • Sun Exposure: Full sun to part shade
  • Soil Type: Average, medium to moist, well-draining,
  • Soil pH: Acidic to alkaline (6.0-8.0)
  • USDA Hardiness Zones: 3 to 9 

Several species of hardy geranium or cranesbill are grown throughout the South. Though our native species are quite beautiful, European varieties are commonly sold in the US, including Geranium sanguineum and G. macrorrhizum. These species spread by trailing roots or rhizomes to form clumps. They can be divided every two to four years to manage spread and/or propagate plants.

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Coneflower

Summer Phlox, Speedwell, Tickseed, Black-eyed Susan, Agapanthus, Spotted Bellflower, Lamb’s Ear, Cranesbill, Coneflower
  • Botanical Name: Echinacea spp. and cultivars
  • Sun Exposure: Full sun to part shade
  • Soil Type: Average, dry to medium, well-draining,
  • Soil pH: Acidic to alkaline (6.0-8.0)
  • USDA Hardiness Zones: 3 to 8 

Coneflowers are among the most popular native plants grown in gardens thanks to their vibrant summer blooms that attract scores of pollinators and songbirds. These hardy perennials spread to form dense clumps over time. Plants can be divided every four years to maintain plant health, reduce clump size, and propagate new plants.

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