What to plant with Astilbe

1. 
   1

   Ostrich Fern

   Matteuccia struthiopteris 'Ostrich Fern'

   Used together in 91 designs — 14.27× more often than this plant appears in gardens generally.

   Why it works: shares Zones 4–7 with Astilbe; takes the same shade; blooms late spring to Astilbe's mid-summer; adds height behind Astilbe.

   Zones 4–7See plant →
2. 
   2

   Miss Kim Lilac

   Syringa x hyacinthiflora 'Miss Kim'

   Used together in 47 designs — 13.01× more often than this plant appears in gardens generally.

   Why it works: shares Zones 4–8 with Astilbe; blooms mid-spring to Astilbe's mid-summer; adds height behind Astilbe.

   Zones 4–8See plant →
3. 
   3

   Pictum Japanese Painted Fern

   Athyrium niponicum 'Pictum'

   Used together in 201 designs — 11.7× more often than this plant appears in gardens generally.

   Why it works: shares Zones 4–8 with Astilbe; takes the same shade; blooms early spring to Astilbe's mid-summer.

   Zones 4–8See plant →
4. 
   4

   White Nancy dead-nettle

   Lamium maculatum 'White Nancy'

   Used together in 49 designs — 9.47× more often than this plant appears in gardens generally.

   Why it works: shares Zones 4–8 with Astilbe; takes the same shade; blooms late spring to early summer to Astilbe's mid-summer; fills in front of Astilbe.

   Zones 4–8See plant →
5. 
   5

   Luxuriant Bleeding Heart

   Dicentra spectabilis 'Luxuriant'

   Used together in 57 designs — 9.37× more often than this plant appears in gardens generally.

   Why it works: shares Zones 4–9 with Astilbe; takes the same shade; blooms late spring to late summer to Astilbe's mid-summer.

   Zones 4–9See plant →
6. 
   6

   Jack Frost Siberian Bugloss

   Brunnera macrophylla 'Jack Frost'

   Used together in 111 designs — 9.25× more often than this plant appears in gardens generally.

   Why it works: shares Zones 4–8 with Astilbe; takes the same shade; blooms mid-spring to Astilbe's mid-summer.

   Zones 4–8See plant →
7. 
   7

   Japanese Forest Grass

   Hakonechloa macra

   Used together in 56 designs — 9.11× more often than this plant appears in gardens generally.

   Why it works: shares Zones 5–9 with Astilbe; takes the same shade.

   Zones 5–9See plant →
8. 
   8

   Foxglove

   Digitalis purpurea 'Mix'

   Used together in 70 designs — 8.5× more often than this plant appears in gardens generally.

   Why it works: shares Zones 4–9 with Astilbe; blooms late spring to Astilbe's mid-summer; adds height behind Astilbe.

   Zones 4–9See plant →
9. 
   9

   Lady Fern

   Athyrium filix-femina

   Used together in 88 designs — 8× more often than this plant appears in gardens generally.

   Why it works: shares Zones 4–8 with Astilbe; takes the same shade.

   Zones 4–8See plant →
10. 
    10

    Green Spice Coral Bells

    Heuchera americana 'Green Spice'

    Used together in 45 designs — 7.81× more often than this plant appears in gardens generally.

    Why it works: shares Zones 4–9 with Astilbe; takes the same shade; blooms mid-spring to Astilbe's mid-summer; fills in front of Astilbe.

    Zones 4–9See plant →
11. 
    11

    Rockapulco Wisteria Impatiens

    Impatiens walleriana 'Rockapulco Wisteria'

    Used together in 101 designs — 7.48× more often than this plant appears in gardens generally.

    Why it works: takes the same shade; blooms late spring to fall to Astilbe's mid-summer.

    Zone 10See plant →
12. 
    12

    Nakaiana Hosta

    Hosta nakaiana

    Used together in 70 designs — 7.32× more often than this plant appears in gardens generally.

    Why it works: shares Zones 4–8 with Astilbe; takes the same shade; blooms early summer to Astilbe's mid-summer; fills in front of Astilbe.

    Zones 4–8See plant →

Method: we counted every Sow design containing Astilbe (2.4k of them), then scored each other plant by how much more often it appears in those designs than in designs generally (lift), requiring at least 40 shared designs. Ranking by lift rather than raw count is what stops the list collapsing into “the most popular plants”.