Got Ugly Bulb Foliage To Hide?

Tulip 'Queen of Night' and Sedum 'Matrona' (Cornell University)

If you love flowering bulbs, but recoil at the thought of having to look at their withering foliage long after the blooms are gone, Cornell University has good news for you.

Knowing that the right plant combinations could successfully hide fading leaves, researchers at Cornell spent four seasons putting bulb/perennial pairings to the test at the university’s trial gardens in Ithaca, New York.

Their results, including some helpful photos of the two plants progressing together over several weeks, are available on the university’s website: http://www.hort.cornell.edu/combos.

As someone who has mostly tried in vain to effectively pair up plants in ways that really do hide ugly, yellowing foliage, I’m grateful to Cornell for putting real energy into actually testing plant combos to see what works and what doesn’t. When deciding which pairings looked good and worked well together, the researchers considered the same types of things gardeners think about: color, foliage type and texture, bloom times and the rate at which the perennials they planted mature.

At Cornell’s website, you’ll find suggestions for combining perennials with allium, crocus, hyacinth, narcissus, tulips and a few other bulbs. Click on the “Featured Combos” link to see all of the successful pairings, including their “Best 15 Bulb & Perennial Combinations.” One word of caution before you race out and buy some of those bulbs and perennials, though: Ithaca is in hardiness zone 5. So be sure to pick plants that will work in your part of the country.

Here’s a quick peek at some of the combos that made Cornell’s top 15 list. Tulip ‘Parade’ with white bleeding heart (Dicentra spectabilis ‘Alba’), which they liked for the pretty pairing of red and white, as well as the brief time when both the tulips and bleeding heart were in bloom. Tulip ‘Queen of Night’ with Sedum ‘Matrona’: These tall, deep-purple tulips look stunning next to the dark-edged sedum. Don’t like ‘Matrona’? The researchers point out that, really, any sedum with dark-edged leaves would likely work just as well.

Hyacinth 'Jan Bos' and Penstemon 'Husker Red' (Cornell University)

Narcissus ‘Pink Charm’ with snakeroot (Cimicifuga ramosa ‘Brunette’.) When we moved to a new house a few years back and I suddenly had to learn to garden in the shade, I fell in love with snakeroot. So I’m definitely going to try this combination, which the researchers stressed will look best if the narcissi are interspersed with the snakeroot fairly evenly.

And while Cornell singled out the combination of hyacinth ‘Jan Bos’ with Penstemon ‘Husker Red’ for top honors, it seemed like the researchers thought that many cultivars of penstemon and hyacinth could be combined successfully. (You really should see the photo progression of this particular combo on the website.)

How do you create these successful bulb/perennial combos at home? you wonder. The researchers say it’s a snap: “It is just a matter of digging holes and planting bulbs!” Um, I’m thinking that you’re thinking that we’re all thinking it might be a little bit more work than that. Still, if you’re game for trying some of these, and you already have established perennial gardens, walk around this summer and scout for spots where you might incorporate some of their ideas.

If you already have some of the perennials they suggest, you’re in luck because all you’ll need to do is order up the bulbs you need and intersperse them with the perennials this fall. Be careful when digging so you don’t harm the perennials’ roots.

Virginia bluebells

OK, now, could someone please let Cornell know that we need them to start testing good combos of perennials and spring ephemerals? I’ve got a big, beautiful patch of Virginia bluebells (Mertensia virginica) that morphs into a pretty hideous bare patch of dirt come June.

Note: A version of this story appeared in the May/June 2012  issue of Northern Gardener.