Bulbs for Continental climates, Upper Midwest--TOW

J.E. Shields jshields104@insightbb.com
Mon, 21 Apr 2003 14:05:20 PDT
Hi all,

Part 2 of hardy bulbs in my back yard.

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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