Gardeners grow many rose family plants beyond roses themselves. Herbaceous ornamentals and shrubs include lady’s mantle (Alchemilla), goat’s beard (Aruncus), meadowsweet (Filipendula), avens (Geum), burnet (Sanguisorba), false spiraea (Sorbaria), cinquefoil (Potentilla), kerria, spiraea, flowering quince (Chaenomeles), pyracantha, and cotoneaster. Trees include hawthorn (Crataegus), mountain ash (Sorbus), ninebark (Physocarpus), and of course the flowering plums and cherries.
Unfortunately a few of these species are considered invasive: multiflora rose (Rosa multiflora) and wineberry (Rubus phoenicolasius) are two especially bad ones in the mid-Atlantic. And then there’s the horribly prolific Bradford pear, a cultivar of Pyrus calleryana that was selected at the USDA Plant Introduction Station in Glenn Dale, Maryland, at one time a very popular street and landscaping tree. You can find them all over the place now, in quasi-wild situations like in the median of Interstate 95 north of the Washington Beltway. Ever notice all the beautiful white blooming trees there in early spring? Bradford pear.
Despite the prevalence of rosaceous plants in the nursery industry, the major economic importance of the family is from foodstuffs. Here’s a partial list of edibles in the Rosaceae:
- Amelanchier species serviceberry
- Cydonia oblonga quince
- Eriobotrya japonica loquat
- Fragaria species (at least 20, plus hybrids) strawberry
- Malus domestica apple
- Mespilus germanica medlar
- Prunus armeniaca apricot
- Prunus dulcis almond
- Prunus persica nectarine, peach
- Prunus species (several) cherry
- Prunus species (several) plum
- Pyrus communis pear
- Rubus caesius (and about a dozen others) dewberry
- Rubus chamaemorus cloudberry
- Rubus idaeus, R. strigosus, and others red raspberry
- Rubus x loganobaccus* loganberry
- Rubus occidentalis black raspberry
- Rubus ursinus (and others) blackberry
Boysenberry was developed from R. idaeus, R. fruticosus, R. aboriginum, and R. x loganobaccus.*
The above list gives an idea of how complicated the taxonomy of this family must be. Malus domestica is actually a catch-all name, since the genetic history of domesticated apples is incredibly complex. It’s believed that the progenitor of our more than seven thousand known cultivars of apple is M. sieversii, native to western Asia.
Rose family plants form several different types of fruits. The various Prunus species bear drupes (colloquially, stone fruits), which consist of a skin enclosing a fleshy layer of tissue, which surrounds a hard pit or stone, which encloses the seed. Although we call them berries, the fruits of the Rubus species are also drupes, or more specifically they are aggregates of drupelets (a drupelet being nothing more than a small drupe).
Apple, pear, serviceberry, loquat, quince, and medlar produce pomes, a type of fruit in which a skin and fleshy layer enclose a layer of cartilage, which encloses several seeds.
And then there’s accessory fruits, in which tissue not derived from an ovary supports the actual fruits. In the case of Fragaria species the fruits are achenes (dry, hard fruits that don’t split open at maturity). So those annoying “seeds” of strawberries are the real fruits. The fleshy part forms from the enlarged area at the top of the flower stalk.
None of the fruits of rosaceous plants are true berries. In the botanical sense, a berry is an indehiscent fruit (meaning it doesn’t split open at maturity) that consists of a fleshy layer surrounding several or many seeds, and the seeds are not surrounded by a hard shell. So if the rosaceous “berries” are not actually berries, what are? Tomatoes. Grapes. Passionfruit. Bananas. Blueberries.
A few of the rosaceous fruits listed above are native to North America: some of the Amelanchier, Rubus, and Fragaria species. Most of the cultivated Prunus species are Eurasian in origin, though there are some edible plums native to the new world.
next time: the wildflowers
*the lowercase “x” in a botanical name denotes an interspecific (between species) cross