One of my favorite groups of plants is the Protea family. As in Proteas, those immense and gaudy over the top cut flowers that go for $8.00 a pop. And you may say well yes, those grow in Hawaii and they are native to South Africa. Well, the jury is still out on whether we can grow any Proteas here. (There’s progress in that department). But there are others that I dearly love and feel compelled to push on gardeners. The ancient Proteaceae is mostly centered in the Southern Hemisphere and it is from Australia, South America and less so from South Africa-that we can find members that will grow for us.
Specific conditions are not so hard to meet
Right off the bat one thing that you should know about this family is that they are adapted to poor soils. I mean, really shitty stuff- the oldest most worn out soils in the world (Australia) and they have developed certain adaptations to deal with this. Proteoid roots are clusters of dense tiny roots in circular structures that mean to suck the very life from the soil. Along with some microbial activity they are super sensitive. That means that they are susceptible to too many nutrients. They glut and they die. Phosphorus is the one mineral that they have a serious time digesting and to a lesser extent potassium. That means the NPK is pretty much turned upside down for these plants. How do you grow plants that hate fertility? Well, it turns out its a little bit of a trick in pots but in our native soils its not a problem at all. Just do nothing. Neglect is their friend and I will get back to that.
Cold hardy members of the clan
The trick then is to look for members of this family that can take our cold winters- the vast majority of this family is from mild to subtropical to tropical environs. It turns out that since Australia is a big place and there are mountains and mountain valleys where it gets fairly cold that there are specific regions to choose from. These alpine species that occur in the Australian Alps and the higher Mountains of Tasmania have yielded what I think are some of the coolest shrubs we can grow in Portland and the rest of the west slopes of Cascadia. When I research plants I like to go one genus at a time and look at the whole as we say electorate. I swear that if you use this approach you are almost always bound to find a species that will grow in our favored climate. So lets start with the largest genus in the family. Grevilleas.
Whittling it down
344 species of shrubs, ground covers to grand trees. The vast number of Grevilleas are shrubs and almost 99% are native to Australia. They are shrubs by the way because shrubs are adapted to take less water than trees….see how that works? Then you whittle it down to those from high elevations and and cold pockets. That reduces us substantially down to maybe two dozen. Already this is easier to manage. Remember Australia and Tasmania get cold but nothing like Oregon- not even close. Then you do a little research (well, maybe a lot, maybe obsessively a lot) and you look for regions of the world similar to Portland and you look for species and cultivars that are being grown there. Turns out that some people in some similar regions are not as obsessive as you but that is for another time. Another thing to do is to querie your nursery friends in California and find out which of these made it through their all time coldest weather with no damage. Put these two methods together and you have a group of plants to work with.
California is right down the road
Luckily we are in close proximity to California and it is there where just about every Grevillea there is can be grown. Its that pipeline that has allowed species to stray north and be trialled. And there is a long history of certain Grevilleas that have been grown here. The problem is they were usually stuffed in the back of Botanical Gardens- isolated or maybe with one or two Australians like they were in a circus freak show- forgotten oddities. This always made me sad and it turns out that they should be dragged from the shadows into our gardens. That time I reckon is now. At Xera I have experimented with a whole group of this genus and I’ve even done a little breeding and seed selection. We aim to get the cold hardiest, easiest to grow and most spectacular varieties out there for gardeners to try.
Why do we love them so much?
First of all as a whole they are extremely drought tolerant and they seem to relish our winter wet summer dry climate- with little to no coaxing they thrive. Second, they have the coolest flowers- completely different than what we are used to and third they bloom almost year round here. They love it, we love it and Hummingbirds find it almost orgasmic. They range incredibly in leaf size and texture. And they make perfect companions to our drought adapted natives such as Arctostaphylos and Ceanothus- as examples. They require- no, they demand nothing and pay big dividends in return.
A genus made to party
It turns out that Grevilleas are a fecund and promiscuous genus. That is to say that just about everybody crosses with everybody. They know how to party. That means you can get some very different looking plants to cross- unlike many other genus’ with a tighter rein on the gene pool- and the intermediary traits of the very different plants yields a huge range. For instance Grevillea juniperina (Juniper Leaved Spider Flower) with tiny sharp needle foliage can cross with Grevillea victorae- with large entire leaves. The resulting progeny run the gamut in leaf size and flower color. A huge range. One interesting thing that I’ve found is that seedlings from certain plants that are not hardy can actually yield hardy plants. Its a question I do not have the answer to but on more than one occasion I’ve grown plants from seed only to have the parent plant and a good percentage of the offspring freeze and die, while certain seedlings prevail- even sail through undamaged. These plants are planted in ideal conditions just feet apart in the same soil conditions. So that means something else is going on here and it means that you should always test a plant through our coldest weather because you can’t be certain that a seedling will be cold hardy. The reverse is true two cold hardy varieties can yield a tender offspring. So- all should be tested. And through this method we have yielded some exceptional cultivars.
The glory of survival- ignore them
This is information we’ve amassed over the past 15 years. Careful observation and culture. Most importantly you should plant Grevilleas in the warmest possible position in your garden. That is most commonly a south facing slope where cold air can drain by. Warm walls work too but that can inhibit dormancy and lead to problems down the road. So in a HOT position in NATIVE soils. That means do nothing but dig a hole and plant it. I usually give it a cursory watering to settle in the soil but that is it. In my 15 years of growing them here I have yet to see a drought stressed Grevillea. They can be grown in clay soils on slopes if strictly unwatered. They also can benefit from the overhead protection of a tree canopy so long as it is a high canopy that lets in lots of light. If the soil is too fertile you can run into problems with chlorosis and this is the yellowing of new leaves. If this is really a problem you can either spray it with chelated iron or rip it out and try again in another spot. Do not water them. They can be susceptible to phytophthera in wet soils and this can be the kiss of death. DON’T water them. If your Grevillea grows too quickly it may rock, simply stake it up. I usually give mine a good tip pruning in spring too to even out top growth to root mass. Tip pruning will also cause the shrub to bloom. So if you have a big healthy plant that refuses to bloom tip prune it and you may be surprised.
Some other hardy Proteoids
Grevilleas are not the only Proteoid genus there are many others. A personal favorite are the Tasmanian Hakeas. They look like nothing else we grow. Large shrubs with spikes for leaves. They are see through shrubs/small trees and two have proven to be perfectly hardy to cold. Hakea microcarpa has blue green upright growing foliage and in early spring in the leaf axils flossy white fragrant flowers crowd the stems. The other is Hakea epiglottis with more grass green spikes and it has small sulfur yellow flowers in spring that smell like cloves. Both grow to 12′ or so and very quickly. Again, never water.
Another genus from Australia that is successful with very pretty shrubs that look incredibly different are the Lomatias. The 3′ to 4′ tall with finely, lacy leaves of Lomatia tinctoria give it the common name guitar plant and it has 1′ tall spikes of ivory white flowers in late spring that remind me of an impressionist painting. Another much different Lomatia is Lomatia myricoides. It has long thin leaves and clusters of clove scented ivory white flowers in summer. Its an upright arching shrub to 9′ tall. It does seem to tolerate irrigation and it has endured temperatures down to 0ºF- not happily but it survived.
If you are just beginning with this family here are the easiest and most cold hardy varieties that we have grown.
Grevillea australis 3′ x 5′ wide ochre colored small leaved tiny white flowers that smell of honey in spring. A handsome shrub that has been hardy to just below 0ºF. Easy to grow.
Grevillea victorae- 9′ x 6′ wide its a big shrub that is also a GREAT PLANT PICK. Handsome large grey green foliage and orange flowers nearly year round. It can stand a little shade. Also, tip prune to encourage flowering.
Grevillea x ‘Neil Bell’- This has surprised us and after going through 5ºF without a scratch in several gardens well, you gotta give it credit. To 7′ x 7′ with tomato red flowers year round.
Grevillea miqueliana – Round leaf Grevillea is the unoriginal common name. Its a big dense shrub for full blasting sun to light shade- it also tolerates clay soils. Its persisted through the coldest winters of the past 15 years. Sunset colored flowers orange/red/yellow are pendulous and once it starts blooming it blooms year round.
Grevillea juniperina ‘Orange Zest’- Our selection of the Juniper Spider Flower with needle like green leaves and masses of bright orange spidery flowers from late winter to late summer. This is one of two survivors of this species that has handled 5ºF twice and with little more than a few brown twigs. To 3′ tall and 7′ wide. Poor soil.
This is just the tip of the iceberg there other species and more that are coming along and many more worth trying- especially if your garden stays consistently above 10ºF- such as urban Portland. We have slowly been expanding our list- through trial and error. And we will be offering them at our shop for intrepid gardeners. Also, another nursery that specializes in Proteaceous plants if you have to order through mail is Desert Northwest in Sequim, WA.. He offers a great variety too with good information on plant hardiness.
As for the weather, this El Nino will go down as one of the wettest for us on record. And after seeing some information on the strongest El Nino’s it appears that they produce a lot of rain for us. Still, there is absolutely no arctic air in the next few weeks so get ready, get set, its time to garden. We will be opening our retail shop on February 4th. Initial hours will be 10 am to 5pm until March. For questions call 503.236.8563.