Who’s standing tall and alone?

A striking sight in the Sonoran desert is a lone saguaro cactus.

Saguaros (Carnegiea gigantea) provide food and shelter to a surprising number of creatures. This includes humans, who harvest their fruit, and use their skeletons for fences and construction.

These cacti have an amazing variety of adaptations to the desert.

First, check out the color of the stems, a pale green, indicating they contain chlorophyll. Since saguaros do not really have leaves, the stems have to do the work of photosynthesizing and producing food. The pale color keeps the plants from absorbing too much hot sunlight and getting burned.

If you look closely, you will see lines of defensive thorns on vertical accordion ridges. The whole plant can expand to hold more water after a good rain, then accordion back in as it uses the water

What you can’t see is the root structure. Instead of sending down a big tap root, like many plants, they send out numerous very long horizontal roots near the surface, to better gather any moisture nearby.

That’s why they’re lonesome looking—they need to grow far apart. And that’s why, in the old days before we realized it was unethical, (now it’s also illegal) people would dig them up in the desert, transplant them, and they would die, because the majority of  the root structure was left behind.

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Ocotillos and visitors

So, the original idea here was to talk about how Ocotillo plants (Fouquieria splendens) in bloom seem to host bird or pollinator visitors at almost any time of day.

It seemed like a good idea to do at least one random sample of observation before declaring this.

And sure enough, during a 3 minute segment one spring afternoon, a few days into full bloom for the ocotillo, there were two bird visitors and several pollinator insects. Now this was just one casual observation, but it indicates how often you see creatures near or on these plants.

As noted in an earlier post, Verdins, (Auriparus flaviceps) the very small birds with yellow heads, are frequent visitors, apparently looking for insects. Finches are also common. And hummingbirds can be seen throughout the year.

It is amazing that any birds can find a firm foothold on the thorny stems. Clever feet.

Remember that the ocotillo is not a cactus, although it may look like one during some parts of the year. It’s in a completely different group. In fact, for most of the year, it looks like a bundle of dead sticks, and if you first saw one for sale in a garden center, you might wonder what they were trying to sell.

One example of right now…

…and right next to you, in the North American Sonoran Desert–quite a variety of flowers along the side of the Phoenix-Las Vegas highway, south of Wickenburg, on March 12: globe mallow, desert lupine, creosote bush, brittle bush, and many others. Amazing that there are so many natives right along the verge.

Again, lower elevations, farther south, means earlier flowering time.

Interesting to watch the populations change even with slight elevation changes, going up and down hills.

Look for places that have not been bulldozed or grazed, so there are fewer weeds and more natives.

Wetlands, swales, ditches, creeks, or washes may have unusual species.

This is prime time for flowers. They change so quickly, it’s worth looking as often as you can.

Right now!

If you want to see amazing flowers in the desert, early March is the peak time.

Chuparosa, palo verde, brittle bush, globe mallow, and many more shrubs have been in full bloom for several weeks now. The agaves are starting to blossom. Annuals are flowering, the spectacular poppies and lupines, as are the interesting little “belly plants,”called that by the researchers and photographers, who have to crawl around on their bellies to study the small ground-hugging plants that sprout, flower, and die back in a matter of weeks.

In lower and hotter elevations, plants bloom sooner. As the season progresses, the active blossoming moves uphill and to the north. Generally, cacti are some of the last to blossom, even out into May.

To take photographs, most people tend to go on a sunny day for brilliant, crisp flower photos. If you can, try taking pictures on an overcast day, or early morning or evening twilight for smooth even light–good for catching details that might be obscured by shadows, and capturing subtle colors.

And if you are lucky enough to get a rainy day, you have a chance for amazing photos, saturated cool colors, and moist, dripping petals on plants which rarely see moist and dripping days.

Check this websigte for useful desert flower photography tips: http://azstateparks.com/rangercam2015/index-3.html

For a list of what is blooming and where in Arizona, check out the Arizona State Parks website: http://azstateparks.com/rangercam2015/index-2.html

And the Desert Botanical Gardens website: http://www.dbg.org/gardening-horticulture/wildflower-infosite

Too Wet!

A surprising limiting factor in some parts of the desert is too much moisture.

Wait, you say, I thought deserts were too dry?

Because there’s usually so little rain, nobody is really prepared for much. So even what might be considered a light rain elsewhere can be enough to flood out desert burrows, nests, hollows, and lowlands. If you are a creature who can move fast, or a plant that can hold its breath, you will get through it.

But even in the desert, rain is not always light. During the summer monsoon months, and a few other times of year, there can be heavy downpours.

And adding to the effect, there’s that old caliche we talked about before. This is the impervious layer of minerals and clay that forms over time a short distance down under the desert surface, and acts as a water-trap. The water can’t sink in–so where it can, it slides off downhill.

With a light rain, you can suddenly get a flash flood. With a heavy, or extended rain, you can get massive dangerous flooding, the kind that kills animals, large as well as small, and washes away trees and cars and buildings.

In the middle of many human habitations in the desert, you will find long empty wild spaces, often called “washes.” These are where the flash floods wash through, carrying away whatever is in their path.

It’s strange, when you think about it, how moisture could be a problem, and a limiting factor, in both directions in the desert.

Or maybe not. Because a lot of living things want conditions that are not too much, or too little. Instead, they want things to be generally within an agreeable range. So when you look at a limiting factor, it can be fun to check if there is another one lurking at the opposite side. Yet another mystery.

Who lives in this cactus?

Who you find living in any particular cactus will depend on when you look.

Many of the large holes in saguaros are originally drilled (although the process sounds more like a jack hammer than a drill) by Gila woodpeckers, who peck into the cactus to hollow out an area for a nest.

One interesting result is that the cactus, always fearful of losing moisture, forms dense scar tissue around the excavated area. This means that when the cactus dies and the flesh falls away, what’s left is the interesting lattice of cactus skeleton, plus an occasional hard rounded shape that looks something like a boot—so it is called a cactus boot. Native people gathered them and used them as containers for liquids.

Back to the cactus-dwellers. While the plant is still alive, these nests drilled inside saguaro cacti are prime real estate, the perfect place to find thorn-protected shelter until the kids grow up and fly away. At first, after the cactus heals and get less gooey, the  Gila Woodpeckers or related birds who excavated the nest holes get first dibs. But later years may bring entirely new sets of residents.

Leafing so soon?

There are leaves and then there are leaves. And then there are cactus pads, like this wide flat prickly pear cactus pad, which are more like stems than leaves.

Because if you look closely, on the surface of this pad, you will see the actual leaves, small succulent pointy cones, next to their associated thorns, which form in the axil (that’s like the armpit!) of the leaves.

The thorns persist, as most desert dwellers know too well, but the little leaves fall off in a matter of days, another water-saving feature, so only the thorns and the thick-skinned pads, and the quickly hardening new pads, remain.

Stems or not, the pads, after the skin and thorns are very carefully removed, have been used for centuries as food by native civilizations in the desert

 

Why Beans?

If you start investigating Sonoran Desert plants, including trees and shrubs, you’ll find quite a few members of the bean family (Fabaceae) represented.

Palo Verde blossoms

That may seem surprising. Why beans? At first glance, your average garden variety green bean plant does not seem especially deserty.

So let’s start with a hidden feature that might be useful in a desert—to deal with poor soil, beans have come up with a clever friendship—they have symbionts, associates, little bacteria that live in nodules, little bumps, in their roots. The beans provide water and sugars to the bacteria, and the bacteria “fix” nitrogen from the soil, turning it into a form the bean plants can use.

And that’s one reason beans are good for you—because of the nitrogen from their little friends, they can make certain essential amino acids, parts of proteins.

Grains like corn or wheat or rice make different amino acids. And it is important for us to eat them together with legumes, another name for beans, to get whole nutrition in one meal. So, for example, we dine on beans and rice, or beans in corn tacos or wheat tortillas, or baked beans with toast, or even a peanut butter sandwich, since peanuts are also a legume.

Humans figured this out a long long time ago, and in fact, they even grew grains and beans together. An essential core of Native American gardens all over North and South America was the trio of beans, corn and squash. The corn provides scaffolding for the beans to climb, and the remains of the bean plants are a source of usable nitrogen for the next year’s corn and squash. To this day, these three continue to play a big role in our gardens, as well as in those huge gardens known as farms.

It turns out that beans also have a bunch of other cool skills for the hot desert—stay tuned!

Limiting Factors—Cold!

If you were in the Sonoran desert in January 2013, you may well have experienced a limiting factor that many people would not expect in a desert: freezing damaging cold.

In many places it dropped into the 20’s or lower at night, for several nights, enough to nip many buds in the bud.

Native plants, which have been through this before, generally survived quite well, but imports, or annual vegetables, either got crisped or completely melted down.

This suggests that planting native species has even more benefits than we usually consider.

Ocotillos and Verdins

This has been a banner year for ocotillos in the Sonoran desert. They started blooming a couple of weeks ago, and have erupted into full orange color. That’s Fouquieria splendens, for all you science types!

Their nectar attracts a variety of insects, making them a favored landing spot for the small olive yellow birds, the verdins (Auriparus flaviceps.) Look for verdins visiting all kinds of flowering plants throughout the summer and fall.