Paeonia tenuifolia
Common name: Fernleaf Peony.
A very different, relatively low-growing herbaceous peony, hardy to USDA Zone 3 or colder, growable from coast to coast in Canada although possibly not exactly a good doer along the east coast in wetter winters. The warmer winters of Vancouver and Victoria are not a cultural problem for this species. In most of the provinces of Canada it is an easy and Low Maintenance plant. Stems of upright habit; height: 1 (to 2) feet. It has a rhizomatous rootstock and established plants can become quite large in area.
Native to SE Europe: relatively widespread through Yugoslavia/ Bulgaria/ Romania/ SW Russia/ Crimea/ Caucasus and a few nearby localized areas.
Its natural habitat is in dry grassland and dry stony hillsides, sometimes in scrub, sometimes on limestone.
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How to Grow:
Easy to grow, very hardy.
Light required: Full sun; possibly some afternoon shade in hotter climates.
Soil: prefers a good sandy loam* to rich loam and may be more sensitive to acidic soil than most other peonies. Requires good winter drainage, being less tolerant of wet soil than most other species, and in drier climates may tend to go dormant in mid- to late- summer unless irrigated i.e. the foliage turns brown and dies down. Has few pests to watch for and is seldom bothered by diseases.
P. tenuifolia doesn't actually do well for me here in N.S., having stayed the same size for the several years I've had it; since it does well in the prairies this may either be an issue of winter wetness or of soil acidity; the wetness I've tried to moderate with what should be good drainage and a mulch of coarse sand. I have seedlings which will be trialled in different areas to find out what I've been doing wrong.
As a footnote, following the relatively colder and drier winter of 2003/04 my older plant has increased its number of shoots at last, and all seedlings planted out in various locations have come up.
One of our growers in Quebec finds that these plants do okay for her in clay soil (in which lactiflora and hybrid peonies are quite happy) only if it is heavily amended with sand to increase drainage; her fields are limed every few years resulting in pH varying from about 6 to 5.4.
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Foliage: Excellent and very different foliage of average density; light green; very fine in texture. Fern-like, yes. Very finely divided, with segments only to about 5mm wide. Wilts at the first fall frost with no ornamentally interesting colour-change here. It is one of those plants that everyone stops at whether it's in flower or not. Emerging foliage is rather cute, resembling something from a Dr. Seuss book or a set of shaving brushes having a bad hair day! Very early to emerge and often gets snowed on here, which makes an even neater picture.
Shoots of P. tenuifolia
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Flowers: Flowers are about 2 to 3 inches in diameter, single, with 5 to 10 petals of satiny blood red to deep crimson, with a showy cluster of yellow anthers in the centre. Semi-cupped and upwards-facing, one per stem. Superb. It is one of the earliest to bloom, being in amongst the blooming period of P. veitchii, P. anomala and P. mloksewitschii here. During 2000, my first tenuifolia blossomed on 2 June. After flowering, the developing carpels are not particularily noteable although they become moreso when they turn brown in fall.
One of the curious things about tenuifolia is that single plants in cultivation tend not to set much seed, if any. Joan Ripley could find only 6 seeds (which she donated to our seed exchange) in a plant colony of what looks in photos like at least a hundred stems. Whether the whole species is not particularily self-fertile is a question that's being looked into, or it may just be that a clone (or a few clones) that are widely distributed happen to be that way. Or they may be quite self-fertile but just in need of a hand to place the pollen. The seeds, when they do form, are much smaller and more elliptical than any other peony seeds, and a nice shiny brown not unlike a mini cod-liver oil capsule.
Flower of P. tenuifolia
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Forms and subspecies: The most commonly grown tenuifolia in North America are the double forms 'Flore Pleno' and 'Rubra Plena' which are either very similar or just two different names for the same clone; it is vigorous, with equally good foliage but apparently more likely to go dormant in late summer than the species itself. It's double flowers are a darker red and curiously it flowers 2 or 3 weeks after the single-flowered ones.
P. tenuifolia 'Rubra Plena'
There is a rare white-flowered form and an even rarer pink-flowered form. Heck, even photos of them are rare!
P. tenuifolia ssp. biebersteiniana from the north Caucasus has a coarser foliage, intermediate between the finer leaf forms of anomala and tenuifolia itself, and to 1.5cm wide.
You may see a P. lithophila (synonym P. tenuifolia ssp lithophila) written up as a dwarf form, but is considered by Halda and others to be within the natural variability of the species and thus subsumed into P. tenuifolia as a synonym.
Availability, as with all the species, is variable from year to year but this species is much sought after and so more usually available than others. It's relatively easy from seed, although slower than some of the species. There are several deliberate and accidental unnamed hybrids out there, all going under the generic name of Fernleaf Peony, which makes for a buyer beware situation with some sources.
P. tenuifolia has been used in the hybridization of a number of fine plants, which tend to be not as finely divided in the foliage but stronger of stem and with foliage which remains fresh throughout the growing season. Flowers of the hybrids tend to be brighter red and not as quick to fade. 'Little Red Gem' is a very good one, and 'Smouthii' is one of the oldest, just by way of two examples.
'Smouthi'
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Garden uses: the flowers are popular with bees of all types. Plants are of a size suitable for Rock Gardens of appropriate scale as well as more traditional perennial border plantings, where they can serve well in front of the taller and later-blooming garden peonies**. They can be used as a taller open groundcover if interplanted with something else to smother weeds, and would go nicely in a wildflower meadow. Plant them anywhere that a different foliage effect is wanted with due regard for the possibility of late-summer dormancy. The flowers are suitable for cut flower arrangements, although not as much so as the garden peonies, but the season is earlier and the colour is glorious.
'Little Red Gem'
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Similar species: None.
As a footnote, the Josef J Halda book The Genus Paeonia is now out and is available from Timber Press. I think this will be a valuable addition to the library of anyone interested in the species plants and well worth the modest price for a book of this quality. The botannical illustrations, both line drawings and colour plates, by his wife Jarmila Haldova more than make up for the absence of photographs. Cultural notes compiled by James Waddick will prove useful to many of us as a starting point when we delve into growing species new to us.
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* Loam: in horticulture, a specific soil composition consisting of roughly equal parts of sand, silt and clay; organic content is not relevant to this definition.
** Garden Peonies: I use this to mean collectively the named cultivars of P. lactiflora and its hybrids.
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Leo Smit
Mt. Uniacke, Nova Scotia
Chair
Species Group of the Canadian Peony Society
Species photos by Leo Smit. Little Red Gem, Smouthi, P. tenuifolia 'Rubra Plena by Lindsay D'Aoust