Botanical Name for This Foamy Bells Plant:
The foamy bells plant that I feature in this article is, in terms of plant taxonomy, X Heucherella 'Solar Power.' The latter part of the name (i.e., the cultivar name) refers both to the plant's color and to its ability to withstand sunlight (as opposed to the shade-craving proclivities of some types of foamy bells).
What the Heck Is a Heucherella?:
If the name, Heucherella sounds "made up," you'll find some justification in learning that the name is an amalgam between Heuchera and Tiarella. There's nothing arbitrary about the name, though: it is thoroughly grounded in the botanical history of this perennial. You see, Heucherella is a hybrid plant, its parents being Heuchera and Tiarella.
Attributes of Heucherella Solar Power:
Technically, this foamy bells plant is listed as being herbaceous. At the warmer end of its range, however, it may grow as an evergreen. Even in the North, I find that my Heucherella 'Solar Power' and other foamy bells plants will provide quite a bit of color right through a mild winter (although the plants are not tall enough to show when the earth is covered in snow).
The plant reaches about 12-18 inches tall (not counting the flowers) with a spread of about 20 inches, and its plant form is mounding. It blooms from May to July, bearing floral spikes that look like little bottle brushes. In terms of color, those blooms give you one more option if you're seeking white flowers for your garden. However, not only are the individual blossoms tiny, but even the floral spike, as a whole, is rather small. So don't expect a knockout floral display.
That's OK with me, because I prize this perennial for its leaves, which are elegantly lobed and variegated. Specifically, the base color ranges from yellow or golden-yellow to lime-green (see below), but that color is punctuated by reddish or purple splotches in the interior of the leaf. Some leaves, though, such as the one in my picture, may have relatively few splotches.
Plant Heucherella 'Solar Power' in growing zones 4-9.
Grow in a well-drained spot that receives full sunlight (especially in the North) to partial shade (afternoon shade is preferable, if you have a choice), and water adequately. The soil preference for foamy bells is a ground into which you have mixed humus, which not only provides nutrients but also helps the soil retain moisture.
Leaf color will depend, to some degree, on the amount of sunshine your Heucherella 'Solar Power' receives. For 'Solar Power' to live up to its sunny name fully and give you golden-yellow leaves, more sunshine is generally better than less sunshine (ramp up your watering efforts accordingly, but without overwatering). You will tend to get a lime-green color, instead, if you grow it in excessive shade. Prolonged periods of dappled sunshine may be the ideal.
I've done the experiment, myself. That is, I grow two of these foamy bells. Specimen #1 is planted up against a stockade fence on the East and is pretty heavily shaded for most of the day by a mock orange shrub, receiving a lot of sun only late in the afternoon. Specimen #2 has golden chain trees and a false cypress for neighbors, but it is situated in such a way that it receives filtered sunlight for most of the day.
And what are the resulting differences in leaf color between the two? Specimen #2 produces more of a golden-yellow leaf, and the foliage has fewer of the reddish-purple splotches. Specimen #1, meanwhile, tends to develop leaves that are more of a lime-green.
Regular care for foamy bells is of a cosmetic nature, consisting of removing dead or dying leaves and deadheading to promote further blooming. The best time to divide them is in spring; experts recommend this operation be performed every few years.
Uses in Landscaping for Foamy Bells:
Use foamy bells as an edging plant, in woodland gardens with filtered sunlight, and as a filler ground cover. By "filler" I mean that, as a small plant, Heucherella 'Solar Power' is ideal for filling up bare spaces in a flower border where there simply wouldn't be enough room for a larger plant.
Because of its colorful leaves, you can use it in certain color combinations that appeal to you. For example, if you like to contrast dark leaves with brighter ones, you could grow Heucherella 'Solar Power' as a foreground plant for Diablo ninebark.
Oustanding Features of This Foamy Bells:
Foamy bells is gaining in popularity due to its beauty as a foliage plant, as an ever-wider selection of colors becomes available and more and more gardeners become aware of it. For an example of another color, see my picture of Sweet Tea Heucherella.
Heucherella 'Solar Power' is thought to be the best gold Heucherella for a sunny location as of the time of this writing (2013). That's a significant point, since the general gardening public tends to think of Heuchera, Heucherella and Tiarella as shade plants.
Why the Common Name, "Foamy Bells"?:
Just as the botanical name, Heucherella is an amalgam of two other botanical names, so the common name, "foamy bells" is an amalgam of two other common names: namely, "foamflower" (Tiarella) and "coral bells" (Heuchera) -- the two parents.
Both parents were named for the appearance of their flowers. A cultivated variety of foamflower with which I'm familiar is 'Sunset Ridge.' But the foamflower native to my region (New England, U.S.) is Tiarella cordifolia.
"Coral bells" is so called for the color and shape of the blooms of Heuchera sanguinea, the type that was most commonly grown for many years. Nowadays, more gardeners grow Heuchera for the colorful leaves of the new varieties. Heuchera 'Blondie' is an example (although it also sports nice -- albeit small -- flowers). Lovers of plants with dark leaves will want to see my picture of a Heuchera with dark foliage.
Like foamy bells, foamflower has a bottle-brush style floral spike. But the flowers of the latter grow more densely, making foamflower a better choice if flowers are more important to you than foliage.
How Can Something With a Soft Name Like "Foamy Bells" Break Rocks?:
OK, now to answer the question implied in my title, which probably stumped all but the most astute among you. Foamy bells (as well as coral bells and foamflower) belong to the Saxifragaceae family. Both the family and one of its genera (namely, Saxifraga) are sometimes referred to as "saxifrage" (pronounced SAK-suh-frij). Let me begin my explanation by providing the etymology behind that name.
Saxifrage derives from two Latin words that mean "rock" and "break," respectively. In what sense can a small perennial be called a "rock breaker"? It seems especially odd to apply it to a plant with a soft-sounding name like "foamy bells," doesn't it?
Some folks jump to the conclusion (I used to be among them) that the "rock breaker" moniker was applied to these plants due to the fact that the native habitat of some of the plants in this family is rocky ground, where the saxifrages grow in crevices. The implication here -- fanciful or otherwise -- is that the plants were responsible for opening up channels between the rocks. But Paul Kennett of The Saxifrage Society says that this isn't so.
According to Kennett, the name alludes not to any rock breaking in the landscape but to the breaking up of kidney stones. That's because "saxifrage" has its roots in superstitious herbalism. A particular type of saxifrage has kidney-shaped leaves, from which fact believers in the "doctrine of signatures" made the assertion that the plant must be good for dissolving kidney stones.
So if you suspected all along that foamy bells was too delicate to be breaking rocks apart on some desolate crag, you were right. I wouldn't count on its dissolving kidney stones, either.