Dwarf Alstroemeria--Topic of the week
Jane McGary (Sun, 29 Jun 2003 22:36:56 PDT)

Mention alstroemerias to many gardeners and they respond, with horror, that
they would never plant any because they are so invasive. This view results
from the prevalence in horticulture of A. ligtu, A. aurea (formerly called
A. aurantiaca), and their hybrids, which do indeed run rapidly below ground
in loose, sandy soils. Their rhizomes plunge deeply, too, so once they are
established in a border, they are difficult to eradicate.

It is wrong, however, to ban alstros (the abbreviation used by enthusiasts)
from our plant collections. This South American genus contains many
small-growing species that are much easier to control. Here are a few of
them from Chile that I have grown, seen in the wild, or both. All of these
can be grown in containers (some as small as 6-inch diameter pots) or in
rock gardens in the warmer Mediterranean climate regions. For more detailed
information, see the "Alpine Garden Society Encyclopaedia of Alpines," vol.
1, pp. 54-60, an entry that I believe was written by John Watson, the
botanist and seed collector.

Alstroemeria exserens can reach 30 cm (1 foot) tall but it has stayed much
smaller here, planted on a big sand berm in the rock garden and not covered
in winter. It has not yet experienced a normally cold winter but has done
well at 25 degrees F (about minus 4 C). The leaves are grayish, and the
flowers are light pink marked with bright yellow and dark red. Seed is
available from Jim & Jenny Archibald's list and often from Watson & Flores.

Alstroemeria hookeri is one of my favorites, grown from Watson seed. The
leafy stems are only about 20 cm (8 in) tall, with glaucous, twisted
foliage. In midsummer it produces a very large number of relatively large
clear pink flowers over a long period. I am growing it in a bulb frame in a
large mesh pot sunk in sand; it has run a little outside the container but
has not self-sown yet, perhaps because I got all the seeds. It is a coastal
plant and probably one of the less hardy species from Chile, and should
make a wonderful addition to coastal California gardens provided it has
sandy soil.

Alstroemeria kingii has bright clear yellow to cream flowers, with
variation in a single population. Those I saw last fall were growing in the
dry sandy bed of a seasonal river near the coast and were flowering on
stems only about 10 cm (4 in.) tall. They appeared as small separate
individuals, not running clumps, but they must have been much disturbed by
the heavy El Nino runoff a few months before. This is not likely to be
frost tolerant but is certainly a candidate for pot culture in the
greenhouse anywhere.

Alstroemeria pallida grows over a fairly wide elevational range and is
usually taller higher up in the mountains. I've been growing a
high-elevation form for about 7 years now in a container plunged in the
bulb frame, where it has experienced temperatures in the low 20s F. It has
grayish foliage and pale pink flowers (there are also white and deeper pink
forms) banded with yellow. I think this one could spread moderately in
loose, gravelly soil where well suited. It is a middle-sized species,
flowering fairly low to the ground but by no means a dwarf plant.

Alstroemeria patagonica comes from the far south of Chile and Argentina,
where it grows in sandy and gravelly places. I collected seed of it in a
sandy "blowout" on the side of a hill, where it was about the only plant
growing in the open sand. It is one of the tiniest species, with very gray
narrow leaves on its 2-4-inch (5-10 cm) stems. Its flowers, however, are
quite showy, being deep golden yellow well spotted in dark red. They appear
in late spring here, where I grow it in a clay pot plunged in the bulb
frame. It has self-sown into the plunge medium, too. It does not seem to
run but I can get small divisions from it when it goes dormant in late
summer. It is not a high-elevation species and probably should not be
expected to survive outdoors in cold continental winters; despite its
latitude, Patagonia is somewhat maritime and not very cold in winter.

Alstroemeria philippii is one of my favorite plants but very difficult for
me to grow. It is quite tender, succumbing to frost at about 28 F (about
minus 2 C), yet it does not grow at all well in a pot in my frost-free
plant room, becoming badly etiolated. When I can get it to flower it is
worth every effort, because this 6- to 8-inch (15-20 cm) plant bears
relatively huge flowers, lilac strongly marked with deep purple--truly
exotic! It sets a little seed in some years and can usually be obtained as
seed from Watson. Gardeners in very warm parts of California should
definitely try it, there is nothing like it--except for the closely related
A. paupercula, which I have not grown yet.

Alstroemeria pseudospathulata is another mountain species, this one plain
bright yellow. My seed-grown plants, in the bulb frame, have not flowered
yet but are remaining a modest size so far. Watson writes that it grows "on
ridges in granite grit to 2500 m" elevation.

Alstroemeria pygmaea is one of the more northerly dwarf species, a
high-elevation plant that may be difficult to manage because of its
latitudinal range (it's hard to tell when Bolivian/Peruvian plants should
go dormant). It is similar to the geographically distinct A. patagonica,
and plants in cultivation under the name A. pygmaea are likely to be A.
patagonica.

Alstroemeria revoluta from central to southern Chile can grow quite tall
but it has stayed short in my bulb frame, as Watson remarks it often does
when its roots are confined. It is an erect grower with rather small,
non-showy pinkish, marked flowers, of interest primarily for its relative
cold-hardiness.

Alstroemeria umbellata is a pretty good-sized plant, but it is rather
prostrate so can be considered "dwarf," I suppose. This is one of the very
succulent-leaved species (A. spathulata, a larger plant, is another) from
mid elevations in the central Chilean Andes. Its stems have thick, gray
leaves with crisped margins, set so closely that they look like rosettes.
In nature it grows in coarse scree or talus, rooting in the finer soil down
below and poking out among the stones. It must be grown "hard" with full
sun and as much cold as it can take (at least 20 F, probably) in order to
remain in character; Watson mentions it has survived on a sheltered slope
in east Scotland. I grew it from seed I collected in 1996 and it has
flowered here for three years now. It is in a mesh pot plunged in the
frame, quite dry in summer but with some residual moisture for its deep
rhizomes, as in nature.

Alstroemeria versicolor is variable in height, high-altitude forms (the
kind I grow) being shorter. Mine flower at about 10 inches (25 cm) tall. It
is erect-growing with narrow, glaucous, twisted leaves. The flowers are
undistinguished in color, a rather muddy yellow/pink blend. It is hardy at
least to 20 F and self-sows enthusiastically, and also spreads from the
rhizome.

Alstroemeria werdermanii is a very rare plant in the wild, growing on
coastal dunes near the Atacama desert, but Watson has introduced it into
cultivation and I grew it from his seeds. It is surviving in the bulb frame
but insisted on flowering this winter in January. Fortunately it was a warm
winter, so it was not harmed, but it probably is a plant best suited to
frost-free areas. The narrow-petaled flowers are interesting with their
elaborate markings.

In addition to those described above, the following species, which I
haven't seen or grown, are described as being of moderate dimensions: A.
andina, A. angustifolia, A. oreas, A. paupercula, A. polyphylla.

Alstros are easy to grow from seed, planted in fall. The young plants
should be kept frost-free and can be potted on once they become dormant in
late summer. If you want to collect the seed, you have to pick it as soon
as the capsule starts to turn yellow. Do not leave it on the plant too
long, because the capsules dehisce explosively, scattering seed hither and
yon (mostly yon). The seeds are attractive to ants, which eat the fleshy
portion and leave the fertile portion to germinate in unexpected places.
Germination is best in cool moist conditions and normally occurs the year
the seeds are planted. Three-year-old plants often flower, especially among
the smaller species. Most species except the very high elevation ones
should be given a dry summer dormancy. In nature they often grow among
shrubs or in rock outcrops, but I suspect they would grow in more
accessible places were it not for the incessant grazing of goats. They do
best in loose, sandy soils and enjoy a liquid feed in fall and spring. If
you are into such things, many species hybridize readily, but I don't think
the dwarf species have been subjected to this much.

Jane McGary
Northwestern Oregon, USA