Pairing Bulbs with Perennials

September 29, 2011

An allium rises above a bed of myosotis "forget-me-nots".

Pairing Bulbs with Perennials--Find Your Favorite Combinations

(by Sally Cunningham (originally written for the Buffalo News, 2010)

One of the joys of gardening is the simple miracle of bulbs.  You plant this pointy little nub in fall, and in spring up pop the flowers!  Bulbs require minimal effort and tolerate many mistakes and poor conditions--from horrible soil to being planted upside down, late in December.  They have their limits (such as beheading by bunnies), but basically are extremely good sports, offering us cheer and beauty, often in the dreariest of seasons.

So why do we often relegate them to isolated little bulb-beds that are only worth looking at for a short time, or stick them in line-ups along paths and driveways?  Why doesn't everybody routinely integrate them with perennials and shrubs, as part of a sequence of bloom that can last through most of the months of the year?

Many gardeners do use bulbs, of course, in wonderful combinations, with annuals, perennials and shrubs, around trees or in planters.  I asked some gardening friends for their favorite pairings and was besieged with great suggestions (what a conversation starter)!  Let these combinations inspire your own creativity.

Allium (ornamental onions, flowering garlic):  'Globemaster' with large hostas 'Sum and Substance', 'Elegans', Guacamole'.  All alliums complement daylilies and many other perennials, including roses.  As Buffalo gardener Gordon Ballard points out, "Alliums come with a bonus:  They are rabbit and deer deterrants, and seem to repel beetle pests...but deadhead them or they'll re-seed like crazy."

Scilla Siberica (squill):  My friend Kathy Guest Shadrack (author and expert on miniature hostas) calls it "a polite blue carpet," surrounding other plants without interference; also nice with dwarf daffodils 'Tete a Tete' or 'Minnow'.

Frittillaria:  Master Gardener Lyn Chimera specializes in native plant gardens, but loves frittillaria's bold oranges and yellows, rising above shorter perennials, and notes that they also may deter rabbits.

Narcissus (daffodils):  Daffodils, especially large ones, mix well with daylilies; the foliage blends in easily and the later daffs can hold their own with rapidly growing daylilies.  Try both early and late flowering narcissus with blue-toned hostas, for wonderful contrast.

Galanthus (snowdrops):  Plant in masses for early interest among later blooming perennials, or with lambs' ears.

Crocus:  International hosta guru, Mike Shadrack, advocates yellow crocus with blue hosta, purples and blues with yellow hosta, white crocus with green hostas--but says, "No multi-colored mixes, please!"  Also try crocus pairings with perennials geraniums, Heuchera (coral bells), and Bergenia--all having attractive foliage still standing in early spring.

Muscari (grape hyacinths):  Scatter among daylilies and coneflowers.

Tulip Hybrids:  Pink 'Angelique' with Lady's Mantle (my personal favorite), 'Queen of the Night' with lambs' ears, orange ones with wine-colored Heuchera.  The possibilities are endless.

Lilies (mostly planted in spring) are essential for summer gardens, but watch for the catalogs and order them early.  While we all want to support local green businesses, this is one category not so well represented in garden centers.  The reason--?  Lilies should be planted the moment you receive them, as they deteriorate (rot) quickly, and garden centers have a problem storing them for you to purchase.

Around shrubs that are standing alone or in hedges, try an underplanting of short bulbs that naturalize--Lilies of the Valley (too aggressive in a mixed border) under hydrangeas, Anemone blanda (windflower) or species tulips around dwarf lilacs or forsythia.

For the sophisticated gardener, careful orchestration with fall-blooming bulbs is rewarding.  Urban gardening expert Carolyn Shaffner is passionate about Colchicum (autumn crocus) and Lycoris, with their spring foliage and startling, bare flowers in fall.  (Lycoris sprengerii is often hardy here--a startling pink with blue highlights). Try them among groundcovers--but mark their presence.  For amazing orange seedheads in fall, plant Arum Italicum next spring (nice with gingers).

Working Out Partnerships

Like any partnership arrangement, it's important to negotiate the deal up front.  Consider the time of bloom, the height of the flowering bulb and the height of the perennial.  You don't want the bulbs to block a perennial's one moment of flowering or vice-versa.  You don't want the bulb foliage, as it is browning, to remain in the spotlight, so you do want to be sure that something else grows tall in front of the declining foliage.  And you probably don't want something magenta flowering next to something red (although color preferences vary greatly among us).

As for cooperation underground, it helps both bulbs and their partners if you can plant them at the same time.  I make it a rule:  never start a new perennial planting without tucking in suitable bulbs in spring or fall of that year, and don't do a bulb bed without some complementary perennials.  I would take it one step farther:  when planting a shrub, tree or hedge, consider providing a skirt or collar of bulbs, perennials or both.  "Give a shrub a skirt," I often say.  Simultaneous planting has several advantages.  You probably removed weeds and prepared the soil.  And neither the bulb nor the perennial's new roots have to compete with already strong, existing roots that will take up all the moisture and nutrients.

On the other hand, you can add bulbs around established plants.  Good bulbs will usually perform even if you just stick them in slits in the ground.  But to plant bulbs correctly with established plants, you should dig holes among the perennials or shrubs, as deeply as the bulbs require, several inches wide.  Mix in some bulb-boosting fertilizer, and then backfill around the bulbs with compost and the original soil, and pat it down.  Or put several bulbs in a trench here and there among the shrubs or other plants.  When you bump into large roots, just move the hole to either side.  For best design, plant all bulbs in casual clumps or drifts, rather than in symmetrical formations, straight lines, or dotted sporadically.

Which Bulbs, Where?

All good gardening requires that you know the plant's tendencies and needs.  Bulbs that multiply like alliums, need room where they won't overrun well-behaved plants.  Daffodils might discourage deer or rabbits, whereas tulips scream to them, "Eat me!"  Frittiliaria are tall, perhaps 3 feet, and the colors are bright orange and yellow, so watch which pastel-colored perennials you choose as bed-mates.  Also, remember how tall the foliage gets, and put tall bulbs behind tall perennials, so the foliage can turn yellow and brown in peace.

A Gradual Approach

I have always put a few more bulbs in every season.  That doesn't mean I now have millions because critters get some, and others--especially tulips--tend to decrease over the years, even when fertilized.  If I could recommend one bulb that everybody should try (and few have it in WNY), it's Camassia, a gorgeous and easy blue-flowering bulb.

Perhaps no other plant group has more impact, more bang-for-the-buck than bulbs, especially those that flower in spring.  Fall is still for planting--so go for it!