Hey, betcha thought a post in late December would be all hollyberries, evergreens and ho ho ho, right? Well, ha ha ha, I'm feeling the Winter Solstice and yearning for yellow as a reminder that sunlight hours will now start, ever so gradually, to increase. So let's take a look forward several months and think about plants that reflect the warmth and sunshine... it's never too early to plan for the season ahead!
Colors in gardening cycle in and out of style, just as in the world of fashion. Blue flowers, white flowers, silver foliage... these classics endure perpetually. Red flowers always have fans, and there are gardeners who build their color schemes around the many shadings of purple, violet and magenta. And I've noticed that after years of being out of vogue, soft fleshy pinks are being snapped up by some of the most stylish nursery customers.
Yellow, on the other hand, is something of a problem child. Many gardeners absolutely loathe yellow flowers... maybe they grew up with too many common, gaudy Marigolds or 'Stella d'Oro' Daylilies, surrounded tragically by yards of red mulch. Whatever the trauma, it's worth a rethink because for one thing, almost every plant comes in a yellow version. That means endless possibilities for creativity in an all-yellow scheme or one that uses yellow as a foil for other colors.
Starting at the beginning of the season, spring bulbs are an easy antidote for the blues of late winter. Most of us grow and love Daffodils, and they come in every shade of yellow from ivory to egg yolk, but they're so well known that I won't discuss them here. Instead consider some other yellow spring bulbs, not so often planted but just as welcome. Species Tulips, like Tulipa dasystemon (left), are more reliably perennial than their taller, showier relatives and excellent for planting around and among emerging perennials. The Winter Aconite, Eranthis hyemalis (center), is always the earliest flower I have, popping up even before the Snowdrops and self-seeding in evenly moist soil where it's most happy. And the elegant Trout Lily, Erythronium x 'Pagoda' (right), is a vigorous hybrid that persists and blooms beautifully year after year in rich, moist soil. Really gorgeous paired with black-red Hellebores.
Among the early blooming perennials are quite a few yellow options, these three for moist soil. Globeflowers, or Trollius (left), are Buttercup relatives that are available in yellows ranging from pale primrose to golden orange. They need consistent moisture and protection from hot afternoon sun, but when happy they will persist, and the tidy clumps gradually increase in size and can be divided after a few years. Primula veris, the Cowslip (center), is the easiest of Primroses and bulks up nicely, though not invasively, in moist shade. Can be divided every other year just after it blooms, and soon you'll have sheets of it in April. And if you have a pond, or a stream, or a bog, or even a ditch, you should be growing the Marsh Marigold, Caltha palustris (right), an American native with beautiful glossy foliage and sprays of golden yellow blossoms. Will grow right at the water's edge, provides early food for bees, deer resistant, self-sows to form a colony in time... what's not to love?
For average to dry soil, in shade, I turn first to the Epimediums. Although they're pricey and slow to increase, they're worth the investment, spreading steadily to form handsome mats of weed-proof foliage after the flush of early spring flowers is past. Two good ones are Epimedium x versicolor 'Sulphureum' (left), and Epimedium x 'Amber Queen' (center), both of which increase as fast as can be expected for an Epimedium. 'Sulphureum' flowers at about 8" but 'Amber Queen' produces sprays of blossom a foot or more in height. A good companion plant is Helleborus x 'Yellow Lady' (right), happy enough in dry shade to survive and flower every year, but if you can enrich the soil just a bit, she'll put on a better display and increase more rapidly.
Shrubs that feature yellow tones in spring are great as a complement and background for Daffodils and Primulas. Plant Forsythia if you must, but I'm content to enjoy it from a speeding car (local garden designer Heather Grimes calls it "The Vomit of Spring"). A much more interesting choice could be made within the genus Cornus, the shrubby Dogwoods. Cornus sericea 'Flaviramea' (left) is a yellow-twigged version of the native red-twigged Dogwood. Forms a nice colony in average to wet soil and bears fruits that feed the birds late in the season. Cornus mas (center) is a large shrub/small tree that blooms very early and sets pretty fruit that looks something like an oval cherry, edible but quite tart and used mainly for jelly in its native home of central and eastern Europe. And for a spectacular focal point in part shade, plant the variegated Pagoda Dogwood 'Golden Shadows' (right). Pagoda Dogwoods, properly Cornus alternifolia, are native to the northeastern US and so-called because of their elegant tiered branching structure. The yellow leaf margins of 'Golden Shadows' make it a standout in the shady understory it prefers, so you only need one!
Yellow flowering trees are uncommon, so the debut of the yellow Magnolias was an exciting event in the world of horticulture. There are quite a number coming onto the market now, but the first of them was 'Elizabeth' (left), hybridized at the Brooklyn Botanic Garden by Dr. Evamaria Sperber in the 1950's. Just shows how long it takes many plants, particularly woody ones, to get from development into our gardens! 'Elizabeth' is a soft ivory color and very beautiful, but if you want a stronger yellow, choose 'Butterflies' (center), a nice primrose yellow, or 'Lois' (right), deeper still and a vigorous grower. Because of their parentage, many of the yellow Magnolias bloom a bit later than the pink and white cultivars, so they're less likely to be spoiled by late frosts.
Euphorbias fill a lull in the season's flowering sequence: they come into bloom along with the later bulbs and remain attractive for a very long time, bridging the gap between high spring and early summer. They are primarily foliage plants, but I think their acid yellow flowers are a refreshingly sharp tonic to the soft colors of many spring bloomers. Most of the larger, dramatic Spurges (their common name) are too tender for us, so we can only drool over them in photos of English and Californian gardens, but the two above are reliable here and I wouldn't garden without them. Euphorbia polychroma 'Bonfire' (left) is a low mounder that stays tidy throughout the season, with colored foliage shading through wine red, bronze and even into tones of violet in the fall, always decorative and interesting. Sometimes tricky to establish (not sure why) but once it takes, it will be with you for many years. Marsh Spurge, Euphorbia palustris (center and right), is a much larger, shrubby cousin that's wonderful used in damp areas. Full sun will yield more flowers but it will also perform well in part shade. It's underappreciated because it looks a bit like a weed in a nursery pot, but once you see it well grown you'll be sold. Has a nice winter silhouette, too.
Coreopsis, or Tickseeds, are an enormous tribe, and hybrids keep coming out every year in lots of luscious new colors, unfortunately not all of them hardy for us here in Zone 5. Three tried-and-true yellows though, are (left to right), 'Moonbeam' with delicate needle-like foliage and flowers a light, bright almost greenish yellow; 'Creme Brulée', with medium textured foliage and larger, butter yellow blooms; and Coreopsis tripteris, the giant of the family from the American prairies, sporting clouds of golden yellow daisies in September atop sturdy 6-9 ft. stems.
No review of yellow-flowering plants would be complete without at least mentioning Daylilies. Enthusiasts go in for the newer pinks, lavenders and reds, but I'm still partial to a good classic yellow, especially when it has a high bud count and looks almost like a wildflower, like 'Wee Willie Winkie' (above). There are so many yellow varieties that you can plan a succession of bloom times to cover almost the whole summer. Other good yellows are 'Corky', short and floriferous with purple-brown buds, 'Berkshire Star', stately at 5 ft. tall with large golden flowers of a true lily shape, and 'Hyperion', the classic lemon yellow that's been popular since it was introduced in 1925.
There's certainly no shortage of yellow daisy-form flowers, many of them American natives that are well adapted to life in our region. One year late in the season I asked local professional gardener Ruth Defoe how she planned to spend the winter, and she replied, "I'm going to finally learn the difference between Helianthus, Heliopsis, and Helenium!" A worthy goal, as they can surely be confusing. Helianthus 'Lemon Queen' (left), is super vigorous to the point of sometimes making a pest of itself, but in the right situation can be a real problem solver. Use it in semi-wild areas where it can be allowed to run rampant, out-compete weeds and cover itself with fresh lemon curd daisies for a very long period in mid- to late summer. Heliopsis 'Summer Nights' (center), is more mannerly, staying in a nice clump and attracting butterflies and other pollinators to its mahogany-centered flowers held on slim dark red stems. The foliage too, is suffused with a reddish tint, giving the whole plant a distinctive look. Best in full sun but will grow and bloom in part shade also. Heleniums come in some delicious shades of brownish red, copper and orange, but the pure yellows, like 'Kanaria' (right), are very useful too. Flat-topped clusters of cute little daisies with prominent button centers bloom for weeks. Older cultivars are very tall (up to 6 ft.) and may need staking, but the newer varieties are shorter and less trouble... just be sure they're sited in a moist soil that never dries out, or you will loose them! Otherwise very easy and rewarding.
More yellow daisies, these all from the genus Rudbeckia! Just about every gardener has grown Rudbeckia 'Goldsturm', available everywhere, super reliable and floriferous... it's a gateway plant for novice gardeners and a workhorse for landscapers. Once you've cut your teeth on 'Goldsturm', you may want to advance to some of its more interesting cousins, all native Americans. Rudbeckia triloba, or Brown-eyed Susan (left), has smaller but profuse blooms that give a more delicate effect among grasses and other perennials. Sometimes short-lived but will usually self-sow, so you'll probably never be without it. Rudbeckia 'Herbstsonne' (center), is thought to be a hybrid between two species, but its origin in unclear. Nevertheless it's a big, beautiful plant with healthy basal foliage and flowering stems that rise to 6 ft. by midsummer producing, over a long period, bright yellow daisies with drooping petals surrounding a very prominent green conical center. My favorite is the giant prairie plant Rudbeckia maxima (right), the Great Coneflower or Cabbage-Leaf Coneflower, so called because its large, glaucous basal foliage does resemble a cabbage leaf. From the base, rigid stems ascend through mid- to late summer that bear the large-coned, yellow daisies. Best planted in groups as each stem may carry only one or two blooms, but unbeatable for providing a vertical accent among lower plants and grasses. All these Rudbeckias are easy, tough plants well adapted to our climate, great pollinator plants, and seed sources for native birds.
To complement all those yellow daisies, something spiky is called for, and here's where we run into some limitations... I can only come up with three (ignoring the thuggish Lysimachia punctata!). Baptisias now come in lots of shades, and 'Carolina Moonlight' (left) is a very beautiful soft yellow. There are stronger yellows too, and lovely blends combining yellow with bronze or reddish purple, all of them extremely easy and long-lived American natives. Another great native is Carolina Lupine, Thermopsis caroliniana (center), a wonderful meadow plant that blooms in early summer and forms decorative seed heads that persist into winter. Finally, I have a sentimental attachment to Hollyhocks, and in spite of their tendency to succumb to rust and Japanese Beetles, I still grow them. The most reliable for me is the Russian Hollyhock, Alcea rugosa (right), a nice blendable lemon yellow that is fairly resistant to rust. Also seems to be more reliably perennial that most Hollyhocks, and there are always seedlings coming along in case the original plant plays out.
Senna marilandica is a big, vigorous almost shrub-like perennial that has a slightly tropical look with its feathery pinnate leaves and clusters of bright pea-like flowers. Formerly known as Cassia marilandica, it's an American native that makes a bold statement used in a flower border, but you've got to stay on top of the seedlings that arise from the decorative seed pods. Used in a meadow, competition from grasses and other forbs will keep its progeny in check, and it provides a nice foliar contrast to most other meadow plants.
Sedums are one of my favorite plant groups... easy, useful and rewarding. They flower in several colors: pink, purplish, white and yellow. I grow some of each color, but keep them carefully segregated because pink and yellow together sets my teeth on edge. Here are three good yellow-flowered types... Sedum kamtschaticum 'Weihenstephaner Gold' (left), an unbeatable weed-suppressing ground cover, Sedum kamtschaticum 'Variegatum' (center), a clumper with refined, cream-edged foliage, and a new favorite of mine, Sedum x 'Lemon Jade' (right). It's a taller plant, similar in scale to the popular 'Autumn Joy', but reliably upright and opening soft primrose yellow from broccoli green buds. The subtle color makes it easy to combine with other late blooming perennials and it looks particularly nice with the seed heads of grasses like Pennisetum 'Hameln' or Bouteloua 'Blonde Ambition'.
Goldenrod, properly Solidago, is a genus well represented in North America with over 100 different species native. Many are so common on roadsides and abandoned fields that it seems unnecessary to include them in our gardens, but here are a couple that are refined and distinctive enough to merit domesticity. Solidago rugosa 'Fireworks' (left), makes a bushy clump, vigorous but not invasive, that explodes in late summer into a shower of golden wands. The effect is quite delicate in spite of the gutsy color, and it makes for a good contrast with Asters, Boltonias and the flowering grasses. Very attractive to bees and butterflies, and tough as nails. Completely different is Solidago caesia (right), the Blue-stem or Wreath Goldenrod. It grows low and spreading, flowering all along its almost horizontal stems. Particularly useful for dry, partly shaded locations where the range of plant options is always limited. It must be mentioned that many people still believe that Goldenrods cause hay fever, but this is simply not the case... Ragweed, which blooms at the same time, is the real culprit!
With a little imagination you can create satisfying combinations using just shades of yellow and yellow-green foliage. This grouping, at the former Loomis Creek Nursery, includes yellow Violas, Verbascum chaixii, a golden conifer, a variegated yellow-twigged Dogwood and some California Poppies. The silvery plant behind is the giant Scotch Thistle, Onopordum acanthium.
There are, of course, many more yellow plants... we've only scratched the surface here. And I'd love to hear from you if you have a favorite I've left out. I hope you've enjoyed this dose of sunshine in the midst of the shortest, gloomiest days, and whatever holidays you celebrate, here's wishing you joy and peace and warmth to come.
Welcome to Sempervivum, an opinionated, sometimes informed and completely unqualified journal of gardens, plants and plantings by artist-gardener Robert Clyde Anderson.