It is time for Garden Bloggers Foliage Day, and this month I am looking at a priority in my desert garden: shade. Structure is good, very important aesthetically in itself; but one aspect of structure is shade, and shade can mean the difference between survival and failure for many plants. A few hours less of direct sun, a slight lowering of the temperature, the effects of shelter and increased humidity under a taller plant, greatly extends the potential success of many perennials here. Unfortunately, this garden is still at a stage where the shade plants themselves are not very tall: a fact most of them are rapidly trying to change!
As the garden is in close proximity to the house and covered patio, I have selected shade plants that remain fairly small. This also allows me to use more of them as their spread will also be proportionately smaller. Most, in fact, could grow either as shrubs or trees; but in the interest of providing upper and lower levels to the garden, I will be training them in tree-form.
The first to go in was a small tree, Acacia salicina, the Willow Acacia of Australia.
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| Acacia salicina at one corner of the East Border. The lemon tree behind is too distant to supply any shade to the garden. |
I am proud to say it is now definitely taller than I am... I can't say much more than that! It grows naturally with a weeping form; and while it has filled out considerably, it has a tendency to add drape at the expense of height. It is reputed to be a fast grower; as I say, this is more evident in diameter than height, but it does supply a good deal more shade to the East Border this summer than last. I have always loved weeping trees, and I look forward to it reaching its anticipated 25 ft (7.5 m) or so, when it should become the dominant structural element and shade source in the garden.
Foliage of Acacia salicina is distinctly silvery and willow-like. It is a friendly tree, thornless, unlike most Acacias native to the US.
Last summer I also added two varieties of Lagerstroemia indica. As I have explained elsewhere, these are from a series of improved hybrids with superior disease-and-drought-resistance. "Dynamite" is the larger of the two. As you can see, it is in full bloom.
At present it is still quite shrubby, although the basic branching system is there for a small, multi-trunked tree form.
Despite the fact we are celebrating garden foliage with this meme, I can't resist adding this picture of bloom!
"Dynamite" is positioned to primarily shade the Central Bed. I have some concerns that it may eventually infringe on the adjacent path, but we shall see.
A second Crape Myrtle, Lagerstroemia indica "Rhapsody in Pink", is planted halfway down the South Border. It is still quite small, but now growing well after a setback late last summer and a slow start this year. Clearly it has a lot of growing to do!
At the southeast corner of the garden I had planted a miniscule Desert Willow, Chilopsis linearis "Lucretia Hamilton". It is the one loss among my shade plants so far, a victim not of heat or drought but of water. It was growing at the intersection of two run-off patterns and so received more water than I realized. As it is a true desert species, this was apparently too much! It is native to waterways in the low desert, but obviously I exceeded its limits. I intend to replace it with the simple species come autumn, as I can purchase a considerably larger plant for a reasonable sum; and, given the current color design in the South Border, its pale pink will do as well or better than the dark purple of "Lucretia Hamilton".
Moving on into the White and Silver Garden, there is another true native of Arizona deserts: Vaquelinia californica, the lovely Arizona rosewood.
This is another plant that grows naturally with a shrubby form, but it is considered a good choice for training to a single-trunked small tree. It is positioned to provide additional shade to both its own section of the garden and the adjacent North Border, as well as forming a visual accent along one of the paths.
Although it is listed with a medium growth rate, mine has put on plenty of height and foliage since planting last winter.
It is a quietly beautiful plant, with white flowers in spring: something I have not yet seen.
Finally, I have begun planting a short allee parallel to the rear of the patio and the Rose Border. I selected Palo Verde "Desert Museum" (Parkinsonia x "Desert Museum") for this area. It is one of the most beautiful trees commonly grown around here, very well adapted, with yellow bloom intermittently for months, and green bark that has a cooling effect in itself.
Foliage is quite small and fine...
I have a second waiting to be planted out in September. Although these trees are very well adapted to heat, it seems wiser to wait till things cool off a little! I look forward to giving the roses some relief from sun with the very gentle shade these trees provide.
With temperatures still quite high, it is easy to stay aware of the need for shade. Already some shade is provided by larger perennials to their smaller neighbors. But leaves and branches that one can walk beneath are still some years away!
Linking with Garden Bloggers Foliage Day at
My Hesperides Garden for this progress report because, as Christina reminds us, it is always good to stop and think about structure in the garden. And shade is certainly part of structure!
Weather Diary: Hot and sunny; High: 110 F (43 C)/Low: 86 F (30 C); Humidity: 11%-27%
Given the horrific heat we had earlier this week (almost cool by comparison to your temperatures!), I think your garden selections may help inform my future plant choices. I've always admired crape myrtles but they didn't do well in the beach cities we formerly lived in, where they were prone to mildew. I suppose the fog we get in our current location could still present an issue in that regard but I may try growing one as it can clearly withstand heat. Have your tried growing any as shrubs rather than trees? A shrub that I could prune below my neighbor's view level may be a better choice for me.
ReplyDeleteMine are still small enough that they are more or less shrubs, and I would think they would grow as well or better that way, Kris. From what I've read, some of the newer hybrids, such as Dynamite, seem to have greatly improved drought tolerance and mildew resistance, so careful selection might really repay the effort! Best of luck!
DeleteHi Amy; I really enjoyed this informative post, thanks for contributing it to GBFD. Almost all the trees you mentioned are unknown to me apart from the Lagerstoemia which I have two of, but they are getting smaller rather than bigger as they hate my free draining soil those I saw last year in North and South Carolina seemed to do better with the higher humidity. I also have to plant in Autumn rather than spring to give plants any chance of survival-
ReplyDeleteMost of the trees I am using (other than the acacia and, of course, the Lagerstroemias) are native to the region. I think they would have a lot of potential for use in other dry parts of the world as they are fairly cold-hardy; but I doubt whether they are much available elsewhere... There is wonderful garden material here, and in Australia also, that has only recently come into use.
DeleteI really love that Willow Acacia...it almost looks like an olive tree with that lovely silvery leaf. Hope it will continue to be a good tree for you. So glad you can enjoy the Lagerstoemia too as that is another great tree. I always notice the color of the soil there...it is so beautiful and seems to cast such a beautiful light..almost a pink tone to it I think.
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