In the Garden Articles

Yellow Flowers

by Joan S. Bolton

On again, off again. That's about as predictable as the summer sun gets on the Central Coast, with a long run of cloudless skies followed by days of our infamous marine layer.

But regardless of what's going on overhead, you can keep your garden sunny and bright by filling it with yellow flowers. The cheery colors will keep your eyes off any gray up above, yet still shine when the sun grows positively intense.

How to Use Yellow

Iris pallida Firebird Coreopsis 01 137 277

The color yellow has universal appeal in the garden, complementing the many shades of green.

While a simple drift of yellow flowers attracts attention, yellow also looks terrific side by side with just about any other color. The strongest, brightest yellows provide perfect contrast to the most vibrant shades of purple, blue, red and orange. Softer yellows blend well with pastel flowers in shades of pink, lavender and white, along with blue-tinged or silver foliage.

Because yellow captures the eye, consider its effect before you select and place your plants. Do you want to dab dollops of sunshine here and there in your garden, or paint broad swaths? Can your other plants stand up to the intensity of the brighter yellows, or would they look better paired with more subtle hues?

Also know that if yellow flowers are planted in close, they may make your garden seem smaller. The eye tends to stop with them, and the rest of the garden quietly recedes into the distance. Conversely, if you plant yellows in the background, they will draw your eye outward, expanding the sense of space.

What to Plant

The following long-blooming perennials and shrubs are just a few of the many yellow-flowering plants that will bring light and warmth to your garden -- even on days when the marine layer refuses to lift.

Gold coin (Asteriscus maritimus) forms a broad ground cover of small, fuzzy, silvery green leaves topped by flat, quarter-sized yellow daisies. Plant it in full sun, as it tends to get leggy in the shade. Gold coin thrives on surprisingly little summer water, and does fine in sandy soil.

Goldie bidens (Bidens ferulifolia 'Goldie') is an ankle-high, compact perennial that pumps out small, gold daisies above mounds of fern-like leaves nonstop from now through November. Then the exhausted plants collapse. Prune them to stumps about 8 inches tall and wide, and they should spring back remarkably well next year.

Coreopsis (Coreopsis grandiflora) is among the finest summer yellows. The first flowers, about 3 inches across, appear on slender stems above narrow, dark-green leaves. The stems then branch out further, providing successive waves of bloom.

You can drive yourself nuts by dead-heading spent blooms every few days. Or do what I do, which is attack the dead flowers every couple of weeks with kitchen scissors, cutting off the flowering stems way down in the clumps of foliage.

In late fall or winter, prune your plants to within 6 to 8 inches to the ground. New branches will sprout from the stubby stems. Volunteer seedlings will also appear, delivering a fresh patch of yellow for the upcoming year.

Euryops daisy (Euryops pectinatus) may be all too common. But despite neglect, drought and wind, the pungent shrub just keeps on blooming, producing medium yellow daisies atop finely cut grayish-green or green leaves. After several years, your Euryops will grow woody at the base. You can try pruning it. But if you cut it back too hard, the new growth may come in lopsided.

Blanket flower or Indian blanket (Gaillardia x grandiflora) is the offspring of two wildflowers native to the central and southwest United States and Mexico. Hairy stems rise above fuzzy, dusty green leaves and bear flat, open-faced flowers in yellow and striped with burgundy and red. As the flowers age, the center disk rises, forming a gumdrop-shaped cone that attracts honeybees.

When flowering declines around Thanksgiving, cut back any leggy stems. The plants will sit quietly over winter. They also readily self sow.

Helianthemum 'Wisley Primrose 03 205 154

Yellow sunrose (Helianthemum mummularia 'Wisley Primrose') blooms most heavily in spring, then sporadically through summer, with demure, cup-shaped, pale yellow flowers hovering above a silvery green mat of leaves.

True to its name, yellow sunrose flowers open with the morning sun and close at night. On overcast days, they are reluctant to open. The plants will tolerate clay soil if you grow them on a slope and are stingy with summer water. Good drainage is key. If sunrose sits in soggy soil, even in winter, it may rot.

Common Sunflower (Helianthus annuus). It used to be that all sunflowers were yellow with brown centers, regardless of how short or tall. These days, you can find sunflowers in shades of yellow, gold, orange, burgundy, russet and even an almost-black. But for many gardeners, yellow reigns supreme.

It's a little late to sow seeds, unless you can find a variety that matures in only 60 days, rather than the more standard 110 days. Sunflower heads really do lift their heads to the sun. Locate the plants so that their heads will face the garden, rather than turn away.

Yellow daylilies (Hemerocallis) range from the diminutive Bitsy, a nearly nonstop bloomer with bluish-green strappy leaves, to the regal Hyperion, a popular old-timer with large, fragrant flowers. Starburst Yellow and Betty Woods are other fine choices.

Daylilies tolerate all kinds of soil. They will survive with little water, but bloom far more prolifically with regular irrigation.

Phlomis fruticosa 'Grande Verde' 01 137 222

Red-hot poker (Kniphofia) is a bit of an odd name, given that the torch-like plumes are an outrageous, candy corn combination of yellow and orange. Some named varieties come in solid colors, such as the all-yellow Yellow Maid and the all-orange Orange Flame.

The strappy-leaved plants look a little rough, and are probably best in the mid-range to back of the garden, where their vivid blooms will light up distant views. They look terrific planted in drifts. The hottest, sunniest spot in your garden will yield the best flowers.

Jerusalem sage (Phlomis fruticosa 'Grande Verde') is a robust shrub that bears spikes of yellow flowers above large, fuzzy, arrowhead-shaped leaves most of the year. It spreads 5 feet wide, 4 feet tall and is a fabulous focal plant. It's especially pretty when planted against a light-colored wall to set off the dark-green foliage.

Yellow roses (Rosa) can be fussy in Central Coast gardens. Two of the most reliable and disease resistant are Graham Thomas and Julia Child. Graham Thomas is a David Austin rose. It forms a towering screen by the end of summer, bearing luscious, cup-shaped flowers of gold toward the tips of its long arms. Julia Child is a compact shrub. She blooms in lemony yellow, grows 3 feet tall and wide, and bears shiny green leaves all the way to the ground.

Green santolina (Santolina virens) is a mounding, knee-high shrub that produces tiny, yellow button-like flowers across the tops of lush, ferny green foliage. Native to the Mediterranean, the plants are remarkably drought tolerant.

By summer's end, the branches tend to flop and open up at the center. As such, avoid planting your santolinas on level ground or on a downward slope. Instead, plant them on an upward slope where they will form a billowy mass of yellow and green.

# # #

Other Terrific Yellows

When considering yellow flowers, don't forget annuals, vines, trees and native plants.

Cheery seasonal yellows include marigolds, calendulas and million bells (Calibrachoa), which is technically a perennial, but often grown as an annual.

Cup-of-gold vine (Solandra maxima) bears enormous, cup-shaped flowers with a mahogany stripe down the center of each petal. Yellow orchid vine (Mascagnia macroptera) produces dainty yellow flowers, followed by greenish-yellow seed pods.

Ray's cassia (Senna splendida 'Ray's Splendor') is a small, nondescript tree until it blooms in late winter and spring with an abundance of golden yellow flowers. Yellow oleander (Thevetia peruviana) forms a glossy-green dome and bears yellow, bugle-shaped flowers most of the year.

Our native giant coreopsis or sea dahlia (Coreopsis gigantea) is a much beloved sight in the Guadalupe Dunes and other coastal bluff tops along the Central Coast. Its thick bare stem looks like an elephant trunk; its leaves are ferny like carrot leaves, and its large, yellow daisy flowers spring out the top.

Island bush poppy (Dendromecon harfordii) is a far more ordinary looking native. The large shrub bears flat, yellow flowers above tidy, bluish-green leaves.

Flannel bush (Fremontodendron) is a fast-growing, very large shrub or small tree that bears wooly green leaves and yellow or gold slightly cupped flowers. The native prefers perfect drainage and absolutely no summer water.

Seeds of Wisdom

A few more reliable yellows for the Central Coast include tuberous begonia, canna, Lemon Drops fortnight lily (Dietes 'Lemon Drops'), bearded iris, Oregon grape (Mahonia aquifolium), black-eyed Susan (Rudbeckia), jelly bean sedum (Sedum pachyphyllum) and Mexican marigold (Tagetes lemmonii).