TOW--Bulbs for Pacific Northwest Gardens

Jane McGary
Thu, 23 Jan 2003 19:41:53 PST
OK, here is a quick and dirty response to the TOW. My garden is at 1600 feet elevation (about 500 m) in the western Cascades and gets about 45 inches of rain per year, from October to June. Average winter minimum is around 15 Fahrenheit (-10 C) but about every fourth year it gets much lower. Summers are cooler than at Ernie O'Byrne's place. Terrain is sloping. Soil (moderately acidic) is quite well-drained in most places and dries out severely in summer. Huge slug, mouse, and vole populations.

Western American and northern Eurasian alliums are unproblematic here and A. carinatum ssp pulchellum is something of a (very pretty) weed. However, the eastern form of A. cernuum died out. The large Dutch selection and hybrids do not flourish as well as I would wish, perhaps they get too dry in summer.

Like Diane Whitehead I found that not all Anemone coronaria (A. hortensis) types planted stayed around permanently. Her garden is obviously warmer than mine (I cannot grow Rhodohypoxis in the open, e.g.) so it is not cold that gets them. A. blanda, A. appenina, A. nemorosa, and A. trifolia are all good, and of course there are the beautiful natives A. oregana and A. deltoidea, the latter native on my place but it gets shaded out.

Many brodiaeas are good, though they do not increase as well as they do in the frames. Dichelostemma ida=maia has done well but D. volubile has not. D. congestum wants it a bit drier, I think. Triteleia laxa survives but does not increase fast--I have 'queen Fabiola' and 'Humboldt Star' in the open. T. ixioides 'Starlight' did not do well planted out.

All species of Camassia flourish, and if you don't like the big ones, try 'Orion', which is a dwarf deep blue oddity.

Chionodoxa (the commercial kinds)thrive and self-sow, but not a problem because the leaves are so small and disappear so soon, and it does not form big clumps like Muscari.

Colchicums - many do well, especially the big Dutch speciosum/bivonae hybrids and C. agrippinum, and C, speciosum itself. By the way, C. autumnale 'Waterlily' appears to be virused, I cannot establish it and no longer try; there is a healthy double, and also I have a double white ('Alboplenum') that does well in the open. The small and spring-flowering colchicums are marginal in the open though I have a couple surviving.

Convallaria (lily of the valley) is shunned as an invasive plant by many gardeners here but I consider it a luxury for its scented flowers, but then I have lots of room that I have no time to maintain and so welcome a groundcover.

Crocuses are sadly subject to rodent predation in the open but I plant lots of the cheap kinds out every year. C. tommasinianus naturalizes well in grass, and C. speciosus seems not to get eaten. There are plenty around despite the mice. Note, however, that not all species are cold-hardy, particularly C. goulimyi.

Cyclamen (hardy species) - here, that would be C. hederifolium, purpurascens (incl. fatrense), and coum; Cc. cilicium has perished in a cold winter, and some of the other probably hardy ones are too tiny to put out in the garden until I have more.

Eranthis I do not grow in the open because the slugs destroy the flowers.

Eremurus grow but do not flourish here; the winters are too wet, I think.

Erythronium - Most species flourish in lower-elevation gardens, but E. multiscapoideum didn't like it outdoors here, nor did E. helenae. E. revolutum, oreganum, tuolumnense (some consider it a pest), and hybrids are good here.

Fritillarias grown outdoors here include meleagris (you have to put it in retentive soil that doesn't dry out in summer), pyrenaica, affinis, the ugly form of F. persica now distributed as 'Adiyaman' (I have the real one too, in the frame!), pallidiflora. Obviously I will be trying more and more as I build up the stock. I have a big rock garden where many should do OK. The big problem is predation (mostly slugs).

Galanthus - Many are perfect permanent plants for the PNW. 'Atkinsii' is in flower now, and nivalis about to be; elwesii and plicatus are also standards. I have G. fosteri on the rock garden.

Gladiolus - I'm growing some Eurasian ones in the open, and G. kotschyanus does particularly well in retentive soil. African ones cannot be grown here.

Habranthus (coastal Oregon) - not here.

Hyacinthoides - "bluebells" are considered a vicious weed by many here, particularly the hybrid ones and H. campanulata, but they are useful growing under shrubs, in groundcover, etc. I like the pink H. campanulata in sweet woodruff (another awful weed).

Hyacinthus orientalis - surprisingly, one of the most permanent plants in my garden, increasing slowly to little colonies over many years. I have both cultivars and plants of the wild form grown from seed.

Iris - the best bulbous iris for me is I. latifolia ('English iris'). I. reticulata forms are so diseased, I have given up growing them. I have some of the easy junos in the rock garden but they do much better under cover.

Leucojum vernum does not flourish here in the open, though it is great at lower elevations.

Lilium - I no longer attempt to grow them because of predation.

Muscari - many are awful pests and should only be planted under trees and shrubs where no other small plants are to be grown. You will never get rid of the bulblets once they get started. There are some non-invasive ones, and remarkably, M. muscarimi and M. macrocarpum are hardy here, though not increasing much.

Narcissus are the obvious standby everywhere, and it seems to be true that if you plant them in the shade of deciduous trees, the bulb flies will not damage them so much. However, many tazetta types do not survive winters here -- though N. panizzianus has, to my surprise. N. bulbocodium ssp obesus is the best "hoop petticoat" for outdoors here, and 'Golden Bells' is doing OK.

Nerine I cannot flower even in the greenhouse.

Ornithogalum is another potential thug, particularly O. umbellatum 'star of Bethlehem', which is nice naturalized in rough grass. Those I have in the garden include O. nutans, pyrenaicum, narbonense, orthophyllum. I am sure there are plenty that are quite cold-hardy.

Oxalis - O. adenophylla is a standard rock garden plant, wish we had the good color forms you see in the wild though. I do not grow the African ones. The other South American I have in the garden (besides the weeds) is O. squamata, which is marginally hardy.

Puschkinia scilloides - A standard plant, very early, not invasive here.

Scilla - those that make foliage in fall often suffer in wet freezing winters. Otherwise good, especially S. pratensis, lilio-hyacinthus (are those the same?), litardieri, and also S. autumnalis and S. scilloides, fall-bloomers.

Trillium - only the western species flourish here though I have a few of the eastern. T. kurabayashii is the most ornamental in the garden; T. ovatum is site-native but appreciates being moved into rich soil.

Tulipa species - Those that have persisted here include T. hageri, batalinii, linifolia, urumiensis, and some others I can't think of offhand - they are planted where they receive no summer water.

Zephyranthes  - cannot be grown outdoors here.

Alstroemerias growing outdoors are A. aurea, A. pulchra ssp. maxima (gorgeous), and A. exserens. Tried A. pallida but it didn't like it.

Bloomeria crocea surprises me by surviving on the rock garden. 
Jane McGary

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