Bulbs for Continental climates, Upper Midwest--TOW

As a group, the Brodiaea, Dichelostemma, and Triteleia are seriously
neglected in gardens in this part of the world. Many of them appear to be
quite hardy here. I have most of mine growing in a bed where the soil is
mostly clay and is permeated with roots of trees of Staghorn Sumac. They
are on the east side of a line of these small trees, so they get lots of
morning sun and some early afternoon sun as well. Water does not stand
here, and I rarely water the bed in dry weather.

Dichelostemma congestum is doing well here. Its tall white spheres of
star-like flowers appear in early summer. Brodiaea californica does well
too, as does B. purdyi. B. coronaria was grown from seeds from Northwest
Native Seeds. I planted the bulbs out in my raised rock garden last
autumn, and they are coming up now. I've not tried this one in the regular
beds yet; it was said to be quite tender, but my seeds came from cooler sites.

Triteleia are the real gems, however. The well known T. laxa 'Queen
Fabiola' (or 'Koenigin Fabiola') with dark blue flowers in early summer is
growing and blooming in several different locations here. T. ixioides
scabra from the High Sierra also blooms and flowers, and sets seeds here in
the Sumac bed. It's light yellow flowers are star-like and have a dark
midrib stripe. T. bridgesii is doing fine, as is T. hyacinthina, both in
the same bed with the sumancs. T. dudleyi seems to be surviving in another
bed, and so is T. x tubergenii. I have tried to start with the hardiest in
these experimental plantings, but I think we should try more species from
this group too.

Claytonia virginica is naturalizing here, as it is a native. Another
Claytonia has appeared where I dumped some old pots of ungerminated
seeds. C. virginica has narrow linear leaves; these volunteers have leaves
that are wider in the middle, tapering both directions from there to
pointed ends. Then there is a succulent or rock garden Claytonia that we
should try here too. I'd be interested in how the other species of
Claytonia are doing for folks in their gardens.

Eremurus seem to be short-lived perennials here, but worth trying. I
planted some of the Shefford hybrids, and two out of 4 lived for several
winters. I need to get more.

Eranthis is settling down in my woodland garden and has finally started to
seed itself around a bit. I hope it naturalizes more.

Fritillaria -- there have been plenty of comments on frits recently. I
generally find them tough to keep alive.

Gladiolus are not usually considered hardy, but the Eurasian species are
quite reliable here. GG. communis byzantinus, illyricus, italicus, and
best of all, imbricatus, are hardy here and bloom reliably. Even the
common garden shop hybrid glads may come back occasionally for a year or
two. A form of G. italicus known as G. caucasicus seems to me to have a
much prettier flower than G. italicus.

Hymenocallis caroliniana (or occidentalis) is a hardy spider lily that
ranges from the Gulf of Mexico northward along the Mississippi River and
into the Ohio River as far as southern Illinois and southwestern
Indiana. It now lives and blooms in my garden here in central Indiana too,
flowering at the end of July or first week in August. The name(s) applied
to this species and its relatives have resulted in horticultural
confusion. Check in Thad Howard's book or in the Flora of North America.

Ipheion uniflorum and other varieties are fairly hardy here too. I need to
try Rolf Fiedler outdoors in the ground this autumn!

Kniphofia should be hardy here, at least a few of the species and many of
the hybrids could be. My K. northiae survived the winter in the raised
rock garden bed. I'm not sure about K. hirsuta yet -- it survived the
previous winter in the rock garden. K. caulescens in a garden bed did not,
although it survived the previous 3 winters there and even bloomed last
summer. KK. citrina, sarmentosa, and stricta only survive where very well
protected, which in my case means around the south and east sides of my
greenhouse, and mulched well in winter.

Nerine bowdenii is often cited as marginally winter-hardy in USDA zone
6. I have not tested this, but I planted some out in a nursery row last
June and found that they did not survive my summer very well! Brent &
Becky Heath have N. undulata outside their office window in Virginia (USDA
zone 7, probably) and it has survived and bloomed in the ground there over
the years. I have just stuck a few bulbs of Nerine angulata and of my
hybrid N. [filifolia X krigei] into my raised bed rock garden for their
coming trial by frost and freeze.

I would like to hear more comments from others on their experiences with
Nerine varieties outdoors in colder climates.

Sternbergia lutea are so far looking very satisfactory here. They do
better at flowering when in a sandy loam, but they seem to survive even in
a clay loam bed that is mostly clay. They bloom at a time of year, late
summer to autumn, when any flowers are very much appreciated.

Trillium is native here in the Great Lakes region, and T. recurvatum is the
most common here in central Indiana. It does very well in my woodland
garden. I've added TT. grandiflorum, flexipes, catesbaei, luteum, and
several others just this year. I have not tried the West Coast (of North
America) species yet. It is a woodland genus and you need a shade garden
for its members to prosper. These should all be quite hardy here, but the
Southern and Western USA species may be more of a challenge in the colder
parts of the Midwest.

My comments have almost all dealt with marginally hardy plants growing
outdoors here. I have to agree with Boyce that Narcissus and most Iris are
terrific plants for cold climates, and that most Tulipa are a waste of time
and money (even if Boyce was too diplomatic to put it that way!) Indeed,
it is the wasted time that annoys me the most.

Zantedeschia is one that we need to explore further for hardiness. I
planted two large seedlings of Z. aethiopica 'Green Goddess' out in a bed
last summer. I have been growing small seedlings of Zantedeschia species
in pots in coldframes over the winter; I don't yet know whether any of them
made it through this past winter. If they have, I'll put half of them out
there in the ground this summer and leave over the winter.

I've ordered some hybrid callas from the mass market catalogs to try
outdoors in the ground here this coming winter. I've heard of and have
received a few tubers of Zantedeschia cultivars that survive in the ground
in zone 7 and seemingly even in USDA cold zone 6. None have made it for me
yet; however, that may be because I mistreated them too much before they
were eventually planted.

Jim Shields
in central Indiana (USA)

*************************************************
Jim Shields USDA Zone 5 Shields Gardens, Ltd.
P.O. Box 92 WWW: http://www.shieldsgardens.com/
Westfield, Indiana 46074, USA Tel. +1-317-896-3925
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