Saturday, November 19, 2016

A little grevillea action to brighten your pre-Thanksgiving weekend

I love fall in Davis. The days are still warm, and many plants come into their own again after slowing down in the summer. Case in point: grevilleas. These Australian shrubs, members of the Proteaceae family, are right at home in California’s Mediterranean climate. As is the case with so many plants (and people!), they’re at their happiest on the coast, but we can grow quite a few of them here in the Sacramento Valley, about 60 miles inland from San Francisco Bay. In fact, the UC Davis Arboretum has a nice collection of Australian natives that thrive here.

Today I want to show you two grevilleas in our own garden that are flowering right now.

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Grevillea ‘Superb’

Grevillea ‘Superb’ has been with us for 4 1/2 years. I bought it in February 2012 at the UC Santa Cruz Arboretum and first planted it in the backyard. Unfortunately it didn’t receive enough sun there so I moved it into the front yard circa 2014. I’m sure it lost a good chunk of its roots in the process—grevilleas don’t like to be transplanted anyway—and it’s taken a long time to get going again. But this year it’s finally turned the corner. And now it’s blooming.

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The flowers are quite a sight. Out of all grevilleas, this one may be my favorite. Although I reserve the right to change my mind at any time.

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These flowers are something else!

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Even in bud they’re pretty to look at. And the foliage is attractive in its own right. A perfect package, really.

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The second grevillea in bloom right now is ‘Flora Mason’. Like ‘Superb’ it’s a hybrid, and while the flowers are quite a bit smaller, up close they’re just as spectacular.

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Grevillea ‘Flora Mason’

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I bought this Grevillea ‘Flora Mason’ from Jo O'Connell, owner of Australian Native Plants Nursery in Ventura County. She’s one of the country’s leading experts on Australian plants and gave a talk at the UC Botanical Garden in Berkeley in July. ‘Flora Mason’ is still in its 1-gallon nursery pot, waiting to be planted in the backyard.

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In addition to the two flowers you saw above, there are 20+ buds. That’s amazing on a plant less than two feet in height!

More about Grevillea ‘Superb’

Parentage: hybrid of a white-flowered Grevillea banksii from Queensland and Grevillea bipinnatifida from Western Australia

Size (H × W): 3-5 ft. x 3-5 ft.; can be pruned quite aggressively to keep it smaller

Hardy to: 25°F

More about Grevillea ‘Flora Mason’

Parentage: hybrid of Grevillea olivacea and Grevillea preissii, both from Western Australia

Size (H × W): 6 ft. x 5 ft.

Hardy to: 25°F

General cultivation information for grevilleas

Like many proteas, grevilleas need well-draining soil that’s a bit on the acidic side. They hate excessive watering so don’t plant them near a lawn where they get overspray! They are highly sensitive to phosphorus, especially the species from Western Australia, so do not use regular fertilizers. In fact, grevilleas don’t really need to be fertilized but if it makes you feel better, give them a little cottonseed meal once a year.

In Davis, our soil and water is alkaline and some grevilleas are prone to chlorosis under these conditions (the leaves turn yellow). To reduce the alkalinity of the soil, I apply a generous helping of elemental sulfur (looks like lentils) in the late fall just before the rainy season starts. That way the sulfur can gently work its way into the soil and acidify it. Within four to six months, yellow leaves will be green again.

11 comments:

  1. Replies
    1. Thanks! You certainly know how to grow grevilleas well--better than me.

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    2. Just the light non-clay soil and climate, probably. The kind and super-knowledgeable staff at RBG provided some great tips. All the Proteaceae got a cup of sulfur pellets when we got home.

      Now caterpillars are eating the Grevillea flowers--I'm wondering what butterflies they are. I don't mind, if it is a native butterfly.

      The 'Flora Mason' is very pretty, with all the yellow.

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  2. Okay, going out to give my new grevillea some sulfur right now. I just got this one at the arb plant sale. http://www.smgrowers.com/products/plants/plantdisplay.asp?plant_id=1998

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    1. Robin, I also bought one of those Grevillea 'Gilded Dragon'. They were super chlorotic, weren't they? I gave mine sulfur right away, and I think it's starting to green up already.

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  3. Wow! The UC Botanical Garden looks wonderful! I'm thinking a day in Davis needs to be scheduled next year, Gerhard.

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  4. Oh boy! I'm not acquainted with 'Flora Mason' - I'll have to put it on the shopping list for my spring trip up to Jo O'Connell's nursery. I'm also going to be on the look-out for 'Gilded Dragon'/'Magic Lantern', also new to me.

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  5. So beautiful! I'm sure you know how much I wish I could grow these beauties in the ground. My two in containers 'Peaches and Cream' and 'Ned Kelly' are both showing about to bust open blooms, here's hoping!

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  6. 'Superb' lives up to its name! I have a single, small-flowered Grevillea in the ground. I should try one of the large-flowered ones in a pot, that I can overwinter inside the greenhouse. Those flowers would be worth it.

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  7. I am amazed they have proven hardy in Davis, I've always tended to think them less hardy than the projected 25°F, and suspect at 27~28°F. My issues may have more to do with growing them too soft, and new growth initiated in fall making them more susceptible to freeze damage. They all do very well here in Berkeley. Superb is one of my favorites too, Wakiti Sunrise is a similar peachy orange that is hard to find anymore.

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  8. Can't wait to see this once they put on some more size. They're fabulous now, but I'm greedy. :)

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