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Five Summer Blooming Perennials with Yellow Flowers for the Rock Garden

Yellow flowers are bright and perky. They stand out in the garden and can easily be seen. They also go with many other colors and so are easy to use in the garden. Yellow is a warm color and can contrast well with cool colors like blue. It can produce a tropical look with pinks and greens or add to the heat of red. Whatever colors you have in your garden, there is a yellow to enhance the look.

Here are five perennials that bloom in the summer with yellow flowers.

Woolly Yarrow (Achillea tomentosa)
In early spring flat heads of yellow flowers are held on 6’ stems above a low mat of gray fern-like foliage with a wooly texture. Cultivars are available with golden-yellow, pale yellow or lemon yellow flowers.

    Size: 6-12” H x 18”
    Light: Full sun
    Soil: Average, well-drained
    Hardiness: Zones 3-7

Rockrose (Helianthemum nummularium)
The 1-2” wide flowers are produced in loose 4-12 clusters on a low-growing evergreen subshrub that tumbles over rocks with abandon. The leaves are 1-2” long and gray-green. Many cultivars are available differing in color, bloom size, and number of petals. ‘Wisley Primrose’ is a particular attractive one with light yellow flowers

    Size: 1-2’H x 2’ W
    Light: Full sun (part shade in South)
    Soil: Average, well-drained
    Hardiness: Zones 5-7

Trailing St. John’s-wort (Hypericum cerastoides)
There are over 200 species of St. John’s-wort and this is one of the best for the rock garden. With its trailing habit it looks terrific spilling over a wall or clamoring over rock. It forms an evergreen mat of silvery gray-green foliage brightened by intense yellow flowers in mid-summer. As a vigorous grower it makes a good ground cover but may be overwhelming in a small garden.

    Size: 6”H x 18” W
    Light: Full sun
    Soil: Average, moist, well-drained
    Hardiness: Zones 6-8

Alpine Poppy (Papaver alpinum)
The 1” wide saucer-shaped flowers with silky petals open 4-6” above a tuft of 2-6” gray-green leaves on hairy stalks. Similar in appearance to the Iceland poppy only smaller, the plant is short lived but readily reseeds itself. Flowers may be yellow, white, or light orange.

    Size: 8-10” H x 8” W
    Light: Full sun
    Soil: Average, well-drained
    Hardiness: Zones 4-7

Alpine Goldenrod (Solidago cutleri)
A native or northeastern US, alpine goldenrod forms clumps of large leaves with clusters of bright yellow flowers borne on short stems from summer into fall. The cultivar ‘Goldrush’ is superior to the species with a more compact form and 12” height.

    Size: 4-14” H x 12” W
    Light: Full sun
    Soil: Average (tolerates lean), well-drained
    Hardiness: Zones 4-7

All of these plants need well drained soil but St. John’s-wort does not tolerate drought well and should be watered in hot dry periods. All of this also appreciate full sun, although rockrose profits from some shade in the South. None of these are going to do well in the South, however, but St. John’s-sort is likely to fare better than the others.

Rock Garden Pointer