Eucalyptus in Seattle

I am keeping notes on each year's progress.  Select one of the following.
Spring 1999 planting
Winter 1999 notes
Spring 2000 planting
 

Spring 1999 planting
I received the seeds last season, but am only now getting around to planting them. They were selected for their potential hardiness in Seattle. This last winter it got down to 10'F for a couple of days. I need to go to the University of Washington Arboretum to see what older trees survived this year's extreme temps.

All of the seeds are from the catalog J.L.Hudson, SeedsMan; Star Route 2, Box 337; La Honda, California 94020, USA. This price of this catalog is $1. All the descriptions are quoted from the catalog, which is "uncopyrighted" by Mr. Hudson.

1. Eucalyptus camaldulensis - Red River Gum - EUCA-30
"(= E. rostrata ) To 60-200 feet, with spreading crown. A mighty tree for deep soils. Takes more heat and cold than globulus, & is widely planted throughout the world. Yields exceedingly hard, durable timber. Hardy to 12'-15'F. Germinates in 14 days at 95'F."

November 1999:  Failed to break dormancy with both cold treatment and gibberellic acid.

2. Eucalyptus cinerea - Silver Dollar Gum - EUCA-38
"(= Argyle Apple ) Beautiful, shining, round, silvery grey leaves. Makes excellent cut foliage. To 20-50 feet. Hardy to 14'-17'F. Fast growing; 6 feet per year. Stands wind and drought. Cut back hard."

Feb. 15, 1999: In my project, this species germinated in 7 days with 70' F bottom-heated soil. No cold treatment of the seed required to break dormancy.

3. Eucalyptus coccifera - Tasmanian Snow Gum - EUCA-52
"Frost hardy small tree to 20 feet or so, standing some snow. Attractive blue juvenile foliage. Peeling bark and smooth white trunk. Narrow adult leaves with fine hooked tip. Tasmania. Give seed two weeks cold treatment."

November 1999:  Failed to break dormancy with both cold treatment and gibberellic acid.

4. Eucalyptus globulus - Tasmanian Blue Gum - EUCA-110
"Mighty forest giant 10 150-300 feet. Very aromatic dark green sickle-shaped 6-10" adult leaves. Young leaves oval, silvery. Creamy white 1 1/2" flowers and warty, inch wide seed pods. Bark peels. The most commonly planted species in the U.S. Prized in cold areas as an annual bedding plant or in the greenhouse for its juvenile leaves. Needs deep soil and room. Hardy to 17'-22'F. Leaves yield a powerfully antiseptic medicinal oil. Germinates in 14 days at 77'F. A valuable timber tree. Can grow 7-8 feet a year, and reach 50 feet in 6 years. Very strong wood; 2" cubes have supported 27,000,000 pounds before crushing."

April 1999: Failed to germinate with on first attempt without cold treatment.  Second attempt with cold treatment (1 month in freezer) broke dormancy.

5. Eucalyptus gregsoniana - Wolgan Dwarf Snow Gum - EUCA-117
"Hardy dwarf shrub with glossy light green leaves and clustered flowers. White, mottled bark. N.S.W. Flowers when 6 feet tall. From high elevation, standing some snow. Cold treatment may help seed."

Feb. 15, 1999: In my project, this species germinated in 7 days with 70' F bottom-heated soil. No cold treatment of the seed required to break dormancy.

6. Eucalyptus leucoxylon - White Ironbark - EUCA-154
"(= Yellow Gum ) Very fast growing slender tree to 20-80 feet. White flowers, pendulous branches, grey-green leaves. Free flowering and tolerant of many adverse conditions. To 14'-18'F. One of the hardiest & heaviest Australian woods."

Feb. 15, 1999: In my project, this species germinated in 7 days with 70' F bottom-heated soil. No cold treatment of the seed required to break dormancy.

7. Eucalyptus macrocarpa - Coolgardie Rose - EUCA-166
" =Mottlecah Largest flowered of all Eucalypts. Golfball-sized greyish buds open into 4-7" across flowers. These are borne right on the stem and range from pink to red or white. The huge decorative seedpods are 3" wide, with beautifully marked disk. Grey-blue 4" leaves. A sprawling, almost vinelike shrub to 4-15 feet. Needs dry soil or leaves will blacken. To 8'-12'F. Shelter from wind."

August 1999:  Failed to break dormancy with  and without cold treatment.  Soaking 24 hours in 1000ppm gibberellic acid solution broke dormancy.  Germinated in 7 days with 70' F bottom-heated soil after soak.

September 1999: Single seedling that germinated after gibberellic acid soak was too weak, and has now died.

8. Eucalyptus niphophila - Snow Gum - EUCA-194
"(= pauciflora var. alpina) One of the hardiest species of all, withstanding snow and ice to 5'-10'F. Silvery blue lance-shaped leaves and creamy flowers in 1 1/2" clusters. White peeling bark adds a double meaning to the name. Slow growing to 20 feet, often with a crooked trunk. Picturesque. Needs 6-8 weeks cold treatment to germinate."

August 1999:  Failed to break dormancy with and without cold treatment.  Soaking 24 hours in 1000ppm gibberellic acid solution broke dormancy.  Germinated in 7 days with 70' F bottom-heated soil after soak.

9. Eucalyptus pauciflora - Ghost Gum - EUCA-220
"Striking white trunk and branches, varying to cream, pink, and orange. Wide open-crowned tree to 40 feet, with narrow, grey-green leaves. Very hardy, standing frost and snow to 10'F, and wet soil. The handsome, often twisted trunk and white bark make this one of the most picturesque of the hardy Eucalypts."

August 1999:  Failed to break dormancy with and without cold treatment.  Soaking 24 hours in 1000ppm gibberellic acid solution broke dormancy.  Germinated in 7 days with 70' F bottom-heated soil after soak.

10. Eucalyptus perriniana - Spinning Gum - EUCA-223
"(= Round-leaved Snow Gum) Unusual round silvery grey leaves surround the stem and detach when dry, spinning around the stems in the wind. Attractive straggling small tree to 15-30 feet, with smooth blotched bark. Profuse white flowers in summer. Highest mountains of SE Australia. Hardy, standing some snows to 10'F. Cut back after flowering to produce the unusual juvenile foliage. Give seed 3 week of cold treatment."

August 1999:  Failed to break dormancy with and without cold treatment.  Soaking 24 hours in 1000ppm gibberellic acid solution broke dormancy.  Germinated in 7 days with 70' F bottom-heated soil after soak.

11. Eucalyptus polyanthemos - Red Box - EUCA-229
"(= Silver Dollar Gum) Round grey-green 1 1/2-3" juvenile leaves. Abundant 3-6" clusters of white flowers. Good landscaping tree. Fast to 20-60 feet. Good cut foliage. To 14'-18'F."

Feb. 15, 1999: In my project, this species germinated in 7 days with 70' F bottom-heated soil. No cold treatment of the seed required to break dormancy.

12. Eucalyptus viminalis - Manna Gum - EUCA-310
"(= Ribbon Gum) Tall spreading giant to 50-300 feet, with drooping, willow-like branches. Narrow leaves and white flowers. Shredding bark. Fast growing to 9 feet per year and 30 feet in 5 years. To 12'-15'F. Germinates in 14 days at 77'F. Exudes a sweet, edible manna which is much sought by the aborigines."

Feb. 15, 1999: In my project, this species germinated in 7 days with 70' F bottom-heated soil. No cold treatment of the seed required to break dormancy.

Winter 1999: Review of progress made in the first growing season
Only 3 of the 12 species failed to grow from the J.L. Hudson seed (one germinated, but the seedling was too weak to survive).  Of the 9 that made it, 6 species were planted in the garden at a height of around 6 inches.  The other 3 species are only a couple inches tall inside under a light.  Next season I will get more seed.  With the help of Ian Barclay, I hope to get seed that has superior genes for cold hardiness.

Spring 2000 planting
All of the seed was obtained with the help of Ian Barclay.  Milligan Seeds is a New Zealand company.  Celyn Vale is a Welsh company.  Descriptions in quotes are from Ian's Hardy Eucalyptus pages.  Thanks very much Ian for letting me share your descriptions in my garden diary.

13. Eucalyptus brookeriana - Rocka Rivulet Gum - Tasmania, unknown elevation - Milligan Seeds
"(Victoria and Tasmania)...  It makes a fast-growing, large tree with bright green leaves.  The outstanding feature is the bark, which is usually fibrous near the base, but above 15' it is shed annually to reveal shades of orange-red, green, bronze and cream.  It is one of the fastest-growing species in perpetually cool, wet climates ... Although it does not grow natively in exceptionally cold areas, it is said to be quite adaptable and can probably withstand temperatures down to 10°F.  It is worth trying probably throughout zone 8b and the warmer parts of 8a.  It also tolerates rather poor drainage."

Feb 3, 2000: Planted with no special treatment.

14. Eucalyptus coccifera - Mount Wellington Peppermint - hardiness selected from Dipton NZ - Milligan Seeds
"(Tasmania) From freezing alpine regions, this tree prefers cool summers and usually grows to about 80' in cultivation, shorter in exposed or hot areas.  Somewhat slow to establish, but grows faster with age.  The juvenile leaves are usually green and often purple underneath, produced on warty orangeish-yellow stems, and variable in shape; the mature ones longer and bluish on smooth stems.  Often classified as one of the "Snow Gums." Requires good drainage; is hardy to 1 - 12 F and perhaps slightly lower (that’s pretty darn hardy)."

Feb 3, 2000: Planted with no special treatment.

15. Eucalyptus glaucescens - Tingaringy Gum - Badja Mtn NSW, 4940' - Celyn Vale
"(southeastern New South Wales, northeastern Victoria) Strikingly silver round juvenile leaves packed closely on the stems and peeling white bark characterize this very hardy tree.  It usually grows very fast and fairly tall (to 40 - 90', depending on soil and exposure) in cultivation, and tolerates a wide variety of soils.  This would make an excellent species for cut foliage.  Hardy to 2 - 12 F. "

Feb 3, 2000: Planted with no special treatment.

16. Eucalyptus gunnii ssp divaricata - Divaricata Cider Gum - Miena Tas, 3250' - Celyn Vale
"(Tasmania) differs from E. gunnii in being slightly hardier (to 0 - 7 F), even more fast-growing, and having slightly more pointed whitish leaves.  Safer in cold areas."
Here are some notes on E. gunnii, ... "It is fast-growing and forms a
slender tree with greenish-gray, brown, and/or white bark, and can reach 120' tall in cultivation.  White flowers appear in winter.  The general color of the tree can vary from greenish to an attractive glaucous blue-white.  Also esteemed for its ability to withstand poor soils and waterlogging in winter, though it will grow much faster in well-drained areas with good soil.  Hardy to anywhere from 2 to 13 F."  The sap is tapped to make a "cider".

Feb 3, 2000: Planted with no special treatment.

17. Eucalyptus mannifera ssp elliptica - Brittle Gum - somewhere in Austrailia - Milligan Seeds
"(Australia) ... soft pinkish-blue leaves and pale yellow-orange bark maturing to powdery-white makes this tree immensely attractive.  Australian Aborigines use the white powder to paint their faces.  Should withstand 10 - 14 F, the hardiest subspecies of E. mannifera."

Feb 3, 2000: Planted with no special treatment.

18. Eucalyptus mitchelliana - Mount Buffalo Gum - Mt. Buffalo plateau Vic, 5100' - Milligan Seeds
"(Buffalo Plateau of northeastern Victoria) This is an attractive, weeping tree with slender blue leaves that usually grows rather quickly to 60' or so.  Primarily smooth but slightly ribbony bark is white and/or grey.  Has proven hardy in Scotland (withstands about 4 F)."

Feb 3, 2000: Planted with no special treatment.

19. Eucalyptus nitida - Smithton Peppermint - Tasmania, unknown elevation - Milligan Seeds
"(Tasmania, perhaps mainland Australia) ...  it has grey, green, and yellow bark, shiny leaves, and it is said to be very cold tolerant
(probably about 4 - 14 F)."

Feb 3, 2000: Planted with no special treatment.

20. Eucalyptus obliqua - Messmate Stringybark - location unknown - private collector
"(southeastern Australia, including Tasmania) This was the first Eucalyptus to be identified by anyone from the western world–Captain James Cook named it in 1784 or so, I think.  It is a remarkably tall-growing species (to 300') though it is often stunted in exposed areas. Relatively drought- and shade-tolerant and always straight-trunked, with stringy grey bark and large green oblique leaves; also produces valuable timber where hardy.  Closely resembles E. regnans when young.  Though it is not often considered a hardy species, its remarkably attractive form makes it worth risking: the way the foliage is held in meandering upright clusters seems to recall some kind of cold Australian rainforest, or something.  Hardy to 7 - 16 F."

Feb 3, 2000: Planted with no special treatment.

21. Eucalyptus paliformis - Wadbilliga Ash - Wadbilliga Mtn. NSW - Milligan Seeds
"Rare species.  Seed from hardy provenance in Dipton NZ"

Feb 3, 2000: Planted with no special treatment.

22. Eucalyptus pauciflora ssp niphophilla 'Nungar Plain' - Snow Gum - Nungar Plain NSW - Celyn Vale
"This is considered by many to be the hardiest species of Eucalyptus, though not as fast to recover from cold damage or as tolerant of sudden temperature drops as its slightly less hardy relatives.  E. pauciflora ssp. debeuzevillei is probably hardier.  Contrary to popular belief, it is actually often quite fast and large-growing in cultivation, achieving 80' in 25 years on good soil with 5" silvery-green leaves.  The outstanding feature is the bark, which, on a mature tree, peels in short strips to expose white, tan, reddish-brown, grey, and shiny silver areas all at the same time.  The stems are often orangeish; the leaves are thick, leathery, and bluish-green.  Intolerant of poorly-drained soil.  Hardy to -4 - 12 F. "

Feb 3, 2000: Planted with no special treatment.

23. Eucalyptus pauciflora  - White Sallee - hardy prov. in Southeastern Australia/Tasmania - Milligan Seeds
Same as above from different location.

Feb 3, 2000: Planted with no special treatment.

24. Eucalyptus regnans - Australian Mountain Ash - location unknown  - private collector
"(southeastern Australia, including Tasmania) If this tree is well-known, it is because some confusion exists as to whether or not this is the world’s tallest tree.  It seems the California Redwood (Sequoia sempervirens) is the tallest living tree, reaching a height of 365', but historically taller trees (including redwoods) than that have been measured.  In 1898 a Douglas Fir (Pseudotsuga menziesii) found in a canyon in British Columbia was measured at 402' tall.  As for the Australian Mountain Ash, the tallest one ever recorded measured 464' tall, but that was a long time ago and many people today do not consider that to be a reliable report.  Another tree measured 435' to its broken top in 1872, and was said to have unquestionably been at least 80' taller than that before the top broke off, judging by the thickness of the trunk where it broke.  Now they cannot find this tree anymore–some suggest that the top broke off again down lower, which is why they can’t find a 435' long log on the ground.  Others do not accept this to be a reliable report either and consider the tallest one ever measured to be 373'.  In any case, it is without question the world’s tallest nonconiferous tree.  In cultivation it is a fast-growing tree with a straight trunk, and it has proven much more drought-tolerant than I was expecting it to (it grows naturally in relatively moist areas).  It is one of the “half-barked” eucalypts, meaning that, in mature trees, the bark persists at the base of the trunk but is shed annually above about 20 - 40' up the tree (see also E. delegatensis).  The leaves are bright green when young, becoming slightly more blue-grey in mature foliage but still somewhat greenish.  It makes a magnificent specimen tree and is also valued for its timber where hardy.  Natively it grows in areas subjected to considerable snowfall, but not so much severe cold or sudden drops in temperature--hardy to 11 - 16 F or so.  Unlike most species, this one does not usually form a well-developed lignotuber and is unlikely to regrow if frozen to the ground."

Feb 3, 2000: Planted with no special treatment.

25. Eucalyptus stellulata - Black Sallee - Currango Plain, NSW 3997' - Celyn Vale
"An extremely hardy form of this specie."
"(eastern Victoria, eastern New South Wales) This species has a widely spreading thick crown and makes an ideal shade tree.  It can grow to about 60' tall and has interesting olive green and white peeling bark.  Seems fairly tolerant of poor wet soils and partial shade.  Tiny fruit pods preceded by attractive star-shaped flowers are intriguing.  Very hardy, withstanding 3 - 11 F.  Another relatively well-known hardy eucalypt, and often categorized as one of the "snow gums."

Feb 3, 2000: Planted with no special treatment.

26. Eucalyptus urnigera - Urn Gum - Lake Echo, Tasmania, 2925' - Celyn Vale
"(southeast Tasmania) so named for its funky urn-shaped seed pods.  It has pale-blue juvenile leaves which are variable in size, narrow blue adult leaves, and blotchy bark.  It is reliably symmetrical in an open sheltered situation, and becomes gnarled and picturesque in exposed areas.  Very fast growing, its ultimate height quite variable–anywhere from 55 - 130'.  Hardy to 3 - 11 F."

Feb 3, 2000: Planted with no special treatment.

27. Eucalyptus vernicosa - Varnished Gum - Lake Esperance, Tasmania, 2730' - Celyn Vale
"This species makes a large tree (to 120', sometimes more) that has peeling white bark with tan and cream-colored patches.  It is incredibly fast growing--up to 10' per year, even in a cool-summer climate, and somewhat messy.  Leaves are described as "narrow and soft" often with purple stems, bark shreds and is rather messy at the base; the trunk often has pink or yellowish patches but is mostly cream to white.  Flowers throughout late winter and spring.  Hardy to 4 - 14 F (New Zealand provenances are hardiest, but most in cultivation are on the less hardy side) and recovers from freezes well.  Young trees 2 - 5 years of age are particularly beautiful."

Feb 3, 2000: Planted with no special treatment.

Finding Cold Hardy Eucalyptus
Here are some links useful for identifying which of the 700+ species of eucalyptus are cold hardy.
Want to buy trees instead of growing from seed?  Check out Windmill Outback Nursery. Here is their tree list grouped by hardiness.
The best resource I have found on hardy eucalyptus. Thanks to Ian Barclay.
Species Mapper provided by the Austrailian government
These guys have hundreds of Eucalyptus species for sale with some listed as "alpine" and "cold hardy" in Flora of Austrailia volume 19
A report from South Africa on hardy eucalyptus trial planting