About the Desert Garden, Part 3

Calliandra californica "Baja Red"

What was meant to be the final post in this little series has become two: one to look at the conditions that define the garden itself, and then a last one (which I am very much looking forward to) about the selection of plants for these conditions.

First, about the garden: its beginnings, its location, water, soil, and layout -- the things that give it defining character.

Beginnings

When we moved into the property about two and a half years ago, it contained a house, some small trees...

Happily, some mature fruit trees were already on the property, including a wonderful orange tree and this small grapefruit tree

...and a smattering of "landscape" plants along the front and west side.

The best of the landscape plants are probably the sizeable clumps of Hesperaloe parviflora, with their shrimp pink flowers on 4 to 6 ft stalks.  Most of the other plants are too small to notice.

Everything else was nearly as bare as the moon.  (This on a 2.5 acre lot.)  In retrospect, I am quite sure the grounds must have been bulldozed when the house went on the market.  There is no other way I know to eliminate weeds quite so completely.  And as the first winter wore on, weeds appeared.  Desert soil may be difficult, but it does naturally sustain some life!

The first priority was to put up facilities for our two beloved Morgan horses, which moved with us from Kansas City to San Diego to Arizona.  The corrals, shades, and a small hay shed went into the southeast corner of the property, which proved to have some bearing on the garden later.  With the horses moved in, life began in our little patch of desert.

Johnny, picture by my sister, who kindly let me use it!

At first it was fascinating just to discover the wild plants, most of which were new to me; however, weeds they were (in many cases) and many were prickly and most had a tendency to tangle themselves up in the fur of my sister's mini Schnauzer.  Such are many desert weeds: tough, pertinacious things -- often with teeth of one sort or another.

And besides, one needs a garden!  So during the first summer, I began to plan the garden.

I knew a few things about the location.  1) Western exposures are the most extreme in the desert.  2) Some frost was probable in winter.  I also knew one thing from my previous garden: it is best to locate my plantings in an area which is frequently and easily accessed (by the gardener at any rate).

The rear of the house looks south and is edged from end to end with one of those glorious Arizona roofed patios that supply shade both for outdoor enjoyment and for protection from sun indoors.

The patio plantings are mostly my sister's work, but my small potful of Anigozanthos flavidus (Kangaroo Paws) can be seen at the lower right corner.

My regular trip out to the corrals was from the east of this patio.  So the decision was made to situate the garden along its east side.  This would mean a fairly small area, squeezed in between patio and shed, but I was not about to start big.  I knew that I knew next to nothing about gardening in the desert.  Best to start small and see whether I could achieve anything with the conditions.  Besides, there is always to option to extend the plantings north and south, which I am now doing.

So the first plants went in during early autumn of 2014.  Muhlenbergia "Regal Mist"...

Muhlenbergia blooming in autumn 2015

 ...and Chrysactinia mexicana were the very first additions.

Since when, the garden has been a kaleidoscope of discovery.

Location

The garden slopes downward to the east.  I felt this would be a good choice on two counts: the effect of the western sun would be reduced, and cold air in winter could flow away from the plantings, reducing the chance of frost damage to tender plants.

At a year and a half, I believe the location was a good choice on both counts.  However, the patio roof is actually the best protection from the sun.  As I begin to expand my plantings along the east wall of the house, I think the intensity of light reflected by the house wall is creating rather different conditions there, regardless of protection from westering sunlight.

Then there is the question of frost.  The ability to grow plants sensitive to cold would considerably extend the material available for the garden as there are a number of species otherwise suited to desert conditions.  But the success of frost protection, in its turn, is dependent on just how low the temperatures go and for how long; and last winter was colder than the one before.  There was a bit of damage done, predictably at the lower edge of the garden, but there was also some damage to my very young Hamelia bush up at the top by the wall.  Once again, I feel that the roofed patio affords more protection than the wall itself.  

Russelia equisetiformis "Big Red"
Russelia is native to Mexico and Guatemala and is said to be frost-sensitive, though it can recover from the roots.  Planted just beyond the patio roof, it has never shown any signs of cold damage.

Except just under the patio eaves, I think it is best to rely on plants that can sustain a few degrees of frost.  There will always be the must-try tender plants sold for gardens deeper in town or further south.  But structural plants should have some leeway in the matter of cold!  (I am not too concerned about the Hamelia, as it is recovering and I think it will be sufficiently hardy by next winter or so.)

There have been two effects of the location which I had not foreseen.  The first is wind, which is a factor specific to this garden.  Our property is located just on the edge of open desert, a wide, flat expanse with nothing to break the wind for many miles.  And although we have a locally typical 6 ft concrete block wall around the perimeter, its capacity as a windbreak is limited relative to the scale of the wind.  Ironically, the long patio -- so beneficial in every other way -- forms an excellent wind tunnel.  In the direction of the prevailing winds, of course!

At their worst these are the dessicating winds of June, which have collected intense heat from days of blowing across desert soil.  And the dust-laden wind storms that brown the air and leave grit everywhere.  These winds suck moisture out of everything they bear down on.  It is imperative that plants have sturdy foliage not easily dehydrated.  A windbreak on the west side of the property would be nice, but it would require extra water arrangements.  And in the meantime the garden must survive on its own.  This adds additional emphasis on selecting plants that can thrive in these conditions.

The other unexpected effect of the location is almost humorous.  One way many plants have of coping with these hostile conditions is to open their flowers only when the light is low, e.g. evening/night/morning-blooming plants.  With an east-facing slope plus the intensity of Arizona sunlight, such flowers close quite early in the morning and do not re-open till fairly late, leaving only the closed blooms for most of the day.

Berlandiera lyrata is one plant whose flowers can close quite early in the day if the sun is too intense.  I am hoping that the acacia tree above it will provide enough shade this summer to mitigate the effect!

Water  

Then there is the question of water.  We are actually under no restrictions as to water usage because our property is on well water.  (Again, our arrangements seem to be typical in the rural parts of this region, however unusual elsewhere.)  The well is shared among three homes and, in the absence of a meter, we split the bill equally.  So my water restrictions are based on respect for the neighbors' bills as well as ours (for the electricity used to pump the well).  And of course, the consciousness that the well must continue to support three families plus perhaps eight horses and enough dogs to make a nice-sized pack!  This is definitely an animal-friendly neighborhood.  Happily I am not facing externally imposed restrictions; there is enough to deal with without that!

It makes sense to use drought-tolerant plants in any case, as they are likely to be best adapted to the requirements of this climate.  At the same time, water is the only relief I can offer plants when temperatures soar above 110 F with no relief for days on end.  And I have found that plants that can accept water during the hottest periods are more likely to survive than plants that require completely dry summer conditions, unless they are fully adapted to desert heat.  It is a curious trade-off, but it has limited the use of many otherwise desirable succulents, while encouraging me to experiment with plants from more tropical climates, so long as they have some drought-tolerance.

Soil

One entirely unforeseen issue throughout the garden is the soil.  It has become obvious that the dirt up by the patio is topsoil brought in when the house was built (back in 2005).  It is loose, sandy stuff with a bit of scree on top.  About halfway down the garden, the topsoil is still there, going down perhaps 1 foot or so, where it is replaced by clay.  By the time one reaches the bottom of the garden, the soil is only native clay.  It has the happy effect of providing for a full range of drainage needs, and I wish I had understood this fact when I began as it might have been fun to plant accordingly!

The clay at the bottom has produced one significant difficulty.  I mentioned earlier that we had corrals and a shed built when we moved in.  This was in autumn during one of the wettest years on record.  Needless to say, there was soil compaction.  Naively I expected it to loosen over a couple of winters.  I am wiser now and realize the degree to which I had learned to rely on freeze/thaw cycles in my earlier garden.  Without the effect of frost or even regular, penetrating rains, the ground remins tightly compacted -- the kind of soil that, when dry, must be dug into, then watered, allowed to drain, and dug some more.  Initially I tried to dig patches of it at times when it was soft enough, and surely some good was achieved, especially as I added organic matter as backfill.

Sunflowers planted in one of the "improved" areas of the East Border

But I haven't enough muscle or energy to go through the whole East Border this way, and I am simply trying to regenerate the soil over time, digging as I can and amending as I can.  And, of course, I am trying to restrain myself from planting anything there that requires good drainage.  No matter what I do to amend the soil, the top of the garden is basically gravelly, the bottom is clay.

Layout

In conclusion, the garden proper is a small space at the east end of our patio.  It is laid out as a rectangle bounded by a hedge of rosemary (a hedge still only partially planted!).  It is planned as four borders with a Central Bed which abuts the patio also.

The Central Bed is a mixture of red hues: scarlet to crimson and pink.  The South Border is softer blue to purple to pink...

In the South Border.  Lavendula stoechas "Madrid", beloved of the bees.  Behind is Eremophila hygrophana.

...while the North Border (just begun) is in stronger purples and reds.  It was, in fact, inspired by the colours of a fuschia grown by my aunt!  The East Border, at the bottom of the garden, is primarily in yellows and oranges.  As the most difficult place for growing things, it is also the home of some of the toughest plants though the early addition of an Acacia tree provides some critical shade in summer now.

The East Border from the entrance/exit to the garden, looking toward the pink end of the South Border.  The East Border has gone in slowly as I have tried to gauge what could or could not grow in this difficult area.  During last summer I lost perhaps a third of the plants I had started here!

And finally, I have also begun moving plants into the area along the east wall of the house, a space overlooked by the dining room, which until now has had a prime view of one apricot tree and a pack of weeds.  This new area will be a little more rugged, but it will also give me the opportunity to make a white and silver garden.  I am quite excited about this!

Convolvulus cneorum, newly planted in the new White and Silver Garden

In my next post in the series (the last, I expect!), I will take a look at how I have been selecting plants for the garden.

Weather Diary: Partly cloudy; High (yesterday): 87 F (31 C)/Low: 51 F (11 C)