I saw my first spring star flower, Ipheion uniflorum, at the local botanical gardens in Fukuoka City, Kyushu, Japan about a decade ago. An extensive colony covered a south facing hillside and in early April put on such a show, it was hard to forget. A couple years later I was looking through the bulb racks at a local store and saw this plant for sale – four or five tiny rootless bulbs in a mesh bag.
They didn’t look like much, but I remembered that hillside and quickly bought two bags. Much to my surprise the next spring they flowered a bright, cobalt blue – quite different from the paler flowered plants I saw at the botanical garden. Later I learned that I had bought Ipheion ‘Rolf Fiedler’, the subject of this article.
This dwarf flowering bulb is green in the fall and winter, flowers in the early spring, and goes dormant in the heat of summer. Ipheion bulbs are small, perhaps typically not more than 2 cm long and look very much like a small shallot. This isn’t surprising since this genus is in the onion family (Alliaceae), and when bruised, the leaves and bulbs give off a garlic-like scent. The leaves begin growth once nights start to cool down, around mid fall in my area (zone 9). The 3-5 strap-like leaves never get that long in my experience, so they don’t look weedy or straggly, but rather form nice, tight clumps. The plants spread by thin underground stolons, at the end of which new offsets form. The thin, wiry white roots are typical of an onion relative.
The flowers of I. ‘Rolf Fiedler’ are its greatest asset. They are born singly off a short flowering stem that stands not more than hand high, at least in my specimens. Unlike I. unifolium, the six petals are quite broad and rounded, oval in shape and have a distinctively darker color – a bright cobalt. There is a select clone of ‘Rolf Fiedler’ called ‘Jessie’ that is said to have the deepest color of all. The 2 cm wide flowers are radially symmetric and at their center the yellow-orange anthers provide a nice compliment to the otherwise blue flower. Blooming starts in April in my area, but in warmer places you may have flowers by mid March, or conversely, in colder climates, May. The flower is held more or less flat, but occasionally the petals can reflex a bit. Flowering is generous in healthy clumps and can last for several weeks.
This plant is native to the low coastal hills of Uruguay in full sun. It is apparently native to only a small area unlike I. unifolium which can also be found in Argentina. There has been a lot of confusion about the naming of this plant – for a time it was considered a form of I. unifolium, but most authorities today feel it is a distinct species, though as yet undescribed. It differs from I. unfolium in a number of ways, most notably the richer flower color, and more rounded flower parts, making it not as star shaped. Recently, many botanists place all Ipheion species to two different genera, with the yellow multi-flowered species put into Nothoscordum, and the blue to white single-flowered ones into Tristagma. So, this plant has an identity crisis, being both an undescribed species while at the same time straddling two separate genera!
Given its limited natural range, and its basically frost free habitat, one might think this plant would be rather tender. Interestingly it has shown itself to withstand at least USDA cold hardiness zone 6, while still being happy in zone 9. To put that in perspective, you can grow I. ‘Rolf Fiedler’ from southern New York state clear down to central Florida. Some say that it is a little less cold tolerant than I. unifolium, but apparently not by much. It has been suggested that their cold tolerance might be extended if drainage is excellent, with soggy soils inviting problems.
In nature it grows in acidic, well drained soils that are evenly moist except in the height of summer when they can be quite dry for a short time. In my garden they get copious rainfall (1600+mm annually), especially during the early summer monsoon, right when they are going fully dormant. Later, in August, the oven turns on with average temperatures approaching 30 C, and for about 2-3 weeks it remains fairly dry. Apparently this is exactly what this plant likes since my original handful of bulbs have multiplied many times over, spreading over nearly a meter square. One fall I noticed that a small group began growing a good 20 cm away from the nearest clump and wondered if they seeded in, or spread by underground stolon. I found the latter to be true. To my knowledge, this species has not seeded in my garden. I will inspect their bed more carefully this year to look for evidence of seeding – a real possibility with Iphieon, which can actually be very weedy in some circumstances.
To summarize growing conditions for this dwarf bulb – plant them shallow in a sharp draining, yet moist, gritty loam or sandy soil with a pH range from moderately acid to slightly basic (~5.5 to 7.5). Plant in full sun for best results, particularly if you live in a cooler climate, but they also can handle light shading. Avoid watering in summer during dormancy. Fertilizer may be added as you see fit, but honestly, any good soil can maintain these plants without amendments. Overly acidic soils should be sweetened with lime, and heavy clay soils lightened with porous materials, but watch out for pure sand. If mixed with heavy clay you can end up making concrete! Honestly though, these really are pretty simple plants to grow and flower, probably the closest thing to a no maintenance flowering bulb.
Those living in the mid south should be able to grow this Ipheion with impunity. Even if you live in a slightly colder climate, go ahead and give them a try. They make pretty border plants when mixed with other bulbs, say Muscari or dwarf tulips, or as a mass planting for a subtle, yet impressive show. Ipheion take up so little space, and are so undemanding that it is well worth trying a few – you may just fall in love if you do.