Primula Elatior

The Oxlip
by Fred Knapp

P. elatior habitat includes wet meadows, open woodland, alpine grassland and late snow melt areas, river and stream green belts, and north facing mountain slopes. It can be found commonly from sea level to about 2800 m, and up to a peak of 4000 m. Although often found over calcareous sub-strata, no reference claims a need for lime in the soil. Several do mention that its environment in some of these underlying limestone, or “chalky” clay areas may be oak or beech woods, which usually grow in and reinforce an acidic topsoil or duff. Its distribution is wide, across southern and central Europe from the edges of Spain into the Altai. There are small population clusters only in Great Britain, Spain, the main thrust of Italy, and Sweden, while Norway, Iceland, Ireland, Greece, and the Mediterranean Islands do without. An excellent distribution map can be found in the AGS guide Primulas of Europe and America, by Smith, Burrow and Lowe.

One of our great gardening friends and mentors was a Swiss lady, Marilyn Held, who exchanged plants and techniques with us, including our first primulas. Her garden, heavily relying on minor bulbs and primulas, would submit to planting/transplanting by hand. So many leavenings of organic material, and so regular a regimen of digging, dividing, recombining, etc. had made her arthritic hands as apt a tool as a trowel for working her favorite plants into her soil. Marilyn had a hardy storybook primula, a yellow polyanthus form which throve mightily for her and bid fair to do well for us with her watchful advice. She had recaptured it, growing happily on its own, from a vacant edge of woods just beyond the backyard fence of her rented house near Washington, and later brought it here to Long Island. I, as she, loved it for its character and its cheerful success, but I wanted to know what it was. I did not then have many primula books, but I read what I could find. Reluctantly, dubiously, I concluded it was closest to P elatior. Yet I was pretty sure it could not be. At that time Kris Fenderson was active in APS meetings in the Northeast, and eventually I asked his opinion (although I had not a plant with me). Verbal communications and memory being what they are, I am not certain how much information he gave me, especially on a “could be” basis with no specimen to examine. But I came away with a “perhaps” for P variabilis (a very unconvincing kind of a name) and a definition of the said plant as a primary cross of P veris and P vulgaris, or a descendant of same. I had been given the “False Oxlip,” and did not even know it when told. Somehow, I missed the nexus of “False Oxlip” and its technical synonyms P x variabilis and P x tommasinii so omnipresent in my current quickie literature review. By the way, Richards prefers P x tommasinii, while Fenderson and Smith/Burrow/Lowe are for P x variabilis, as the primary hybrid name. I have no choice but to go for P x variabilis - it begins with a “v.”

If we follow Richards, which surely seems the wiser course, Section Primula now includes P. juliae, megaseifolia and renifolia. Although I have never grown the latter two, I couldn’t be happier to have P.juliae included. From a dirt gardener’s point of view, in the Atlantic seaboard climate as it enfolds USDA hardiness Zones 6-7, the primula world is dominated by the three former Vernales plants, P juliae and their interlocking derivative hybrids. Surely they do belong together.

How does one grow P elatior, and what success have I had on Long Island? Quite a few P elatiors - unverified, but often from quite reliable sources such as Montrose - have resided here for a time, but a time usually not too long, so that I cannot claim to be truly successful with it. I have to agree with Richards’ comment “...splendid rock garden plants, although they are less suitable than cowslips or primroses for naturalizing, being less vigorous in most garden conditions.” This comment is not as drastic as it sounds. It should be taken in context with one mentioned elsewhere in the references, concerning the frequent absence of P elatior from apparently suitable habitat. The plant, rather than needing a different regimen from that of its relatives probably needs closer attention to the regimen. Looking over the habitat summary, perhaps a higher pH or more spring moisture are good places to start experimenting if you do no better than I. Our garden, situated in mature second-growth woodland, has sandy acid soil in most areas, some with pH down to 4.5. Our primula beds are prepared with peat, dried cow-manure, composted chopped leaves, and super-absorbent, all in various unscientific amounts. We top dress with dried cow manure and composted leaves or partially composted chopped tree branches and prunings when available in quantity, and irregularly use liquid fertilizer or sometimes slow release granules more common in potted plants. We use pine needles for a winter mulch. And we do dig and divide plants or entire beds, although not on a dependable schedule. We do not regularly use lime or seek a controlled pH. In areas where this has all taken place nicely, results are gratifying. However, the quality of care is variable, depending on what else is being developed in the garden. In addition, many primulae - generally including P. elatior over the years, since there has never been a P. elatior bed - are planted at the edge of a bed “belonging” to some other primulae, where the merits of the bed may first begin to flag, or simply in a convenient area as companions to other plants. It seems that P. elatior has never been given our garden’s “best shot,” and in return P. elatior has not given back its own “best shot” to us.

For the record, let us run through a description rearranged from the references. The description applies loosely to all sub-species, but is best for P. ssp. elatior, the type plant. The entire plant is hairy wherever green, with 1/4 - 3/4 mm hairs, rarely to 1 mm. Richards notes that these tiny hairs are “crisped,” presumably meaning slightly curled or hooked. Leaves 5-20 cm by 2-7 cm, with rounded tips and usually abrupt contraction at the base, finely toothed. Stem 10-30 cm, stiff and upright. Umbel one sided (secund) and many flowered. Calyx to 1.5 cm, with 5 prominent ridges, cut 1/3 to 1/2 with pointed sepal lobes. Corolla pale to bright yellow, “sulphur” but not golden, with tube longer than calyx, flat to funnel shaped, up to 2-5 cm diameter. Capsule longer than calyx (exserted). Exceptions to this description may be minor, as number of flowers or leaf shape variations, overall size, etc. They may also be major, as the blue to purple coloration of P. e.ssp. meyeri (syn P amoena), or the virtually hairless leaves of P elatior ssp. pallasii.

I was able to assemble 10 primula books to help me with this article - I had not realized there were so many in the house. I consulted them all in order to get the most useful description of P elatior, and I was struck by an unexpected element contained in several of them. The ambiguity mentioned above appears strongly in the descriptions as a defense against confusion with P veris, or with the P veris x P vulgaris hybrid, P x variabilis.

How does one dispel the strong resemblance of some forms of P veris and P elatior to each other? The APS Pictorial Dictionary gives “three useful criteria”: 1) “The calyx lobes of the Oxlip are triangular, finely haired, and pointed; those of the Cowslip less hairy and blunt.” Other references point out that the Oxlip calyx is cut 1/3 to 1/2, that of the Cowslip only1/4 to 1/3. 2) “The capsule exceeds the calyx in length in the Oxlip; it is inferior to the calyx in the Cowslip.” 3) “The throat of the Oxlip is smooth; that of the Cowslip contains distinct folds.”

Other references cite the degree of one sidedness and of modest head hanging, the lack of odor in P elatior, and the baggy or inflated calyx of P veris. These characteristics are among the more variable of one or both species, and thus less certain indicators, but Richards specifically characterizes the hairs of Oxlip as “crisped,” a telling point if you have your hand lens in your pocket.

I believe that anyone reasonably successful in growing Section Primula plants, species or hybrids or both, can learn to succeed with P. elatior by following one simple rule: consider P. elatior your most important plant. This done, you will end by following all the other rules more promptly, more fully and with more responsive awareness of the plant’s progress. Many gardeners have learned to sense a plant’s needs in the limited greenhouse environment; it comes from daily contact, visual and tactile, but it is more sensing than seeing. This innate insight into certain plants is transferable to your “most important” garden plants. Start with P. elatior.

One or two more steps you should consider concern the plants you choose for your P. elatior display. Grow them from seed, especially seed of mixed origin. Grow them also from divisions of any successful forms your friends and contacts in similar areas may have. Plant as many as you can each season. After you and P. elatior have agreed on what forms are best for your garden, seek out varieties and subspecies which seem to fit those plants. You will then be well rewarded by learning to grow Primula elatior in your conditions without any feeling of special care.

Photo Credit: Sally Arant