PALO VERDE NOMENCLATURE
FAMILY: Fabaceae or Leguminosae (Pea family)
FOOTHILLS PALO VERDE (Cercidium microphyllum)
BLUE PALO VERDE (Cercidium floridum)
Tohono O’odham Names: ????
Spanish Names: ¿?
Palo Verde, Spanish for “green pole” or “green stick,” are so named because their trunks and branches are green. In Arizona there are two native Palo Verde species: the Foothills Palo Verde and the Blue Palo Verde. In the desert, Foothills Palo Verde are found on rocky slopes, while Blue Palo Verde tend to grow along arroyos, or washes. Both species make great nurse trees, providing protection for other native plants such as baby saguaro.
Foothills Palo Verde (Cercidium microphyllum) trees have a yellow-green trunk, tiny leaves, and a spine at the end of each branch. Their seeds are large with a seed pod that constricts around them.
Blue Palo Verde (Cercidium floridum) trees have a blue-green trunk, larger leaves, small spines along the branch at the leaf nodes, and no spine at the end of the branch. Blue Palo Verde seed pods are larger pod than Foothills seed pods, and the pod does not constrict around the seeds.
PALO VERDE IN THE URBAN LANDSCAPE
Foothills and Blue Palo Verde are often found in urban landscapes due to the striking colors of their bark and bloom, and their amazing drought tolerance. In early spring, the combination of their bright yellow blooms against their green trunks makes a beautiful addition to any home or neighborhood landscape. The beautiful greenish bark of Foothills and Blue Palo Verde trees contains chlorophyll-bearing tissue, where about three quarters of the tree’s photosynthesis occurs. The remainder occurs mostly in leaves, but also in blossoms and seedpods. The Foothills Palo Verde is the primary “nurse” plants for the saguaro cactus – their ranges across the Sonoran Desert closely overlap. Like Mesquite, Desert Ironwood, and other Fabacaea (legume) family trees, both species of Palo Verdes drop nitrogen-rich leaf, seedpod, branch, blossom, nest, and bird litter to the ground, creating a protected, fertile, and shaded germination zone underneath for vulnerable saguaro cacti and other desert seedlings, whose survival is at risk without such advantages. Many desert animals also take refuge under and obtain food from Palo Verde trees.
PALO VERDE TREE PLANTING RECOMMENDATIONS
Both species of Palo Verde are great trees for the urban landscape and will grow quickly when given supplemental water from a rainwater-harvesting basin. The Blue Palo Verde tree has larger leaves than the Foothills Palo Verde, but both can become great shade trees as they age.
Often around Tucson’s urban areas you will see plantings of non-native species of Palo Verde called Palo Brea (Cercidium praecox), which is from northern Mexico. These tend to bloom later, have small leaves on a long leaf center, and a yellow flower with orange spots. Although beautiful trees, and also drought tolerant, we recommend planting the two native species because their seeds taste better and they create better habitat and food sources for native pollinators and birds.
Native Tree List for Tucson
PALO VERDE HARVESTING BASICS
HARVEST: Like other leguminous desert trees, both species of Palo Verde produce edible flowers and seeds (but many find the Foothill seeds to be sweeter). The trees generally flower in late April through May and then set green seed pods a few weeks after. The green pods will dry in June-July. Both green and dry pods can be harvested, preferably before the summer monsoon rains start.
Green Palo Verde seeds can be harvested when the pod is green and the seed inside has developed but is still small, green, and tender. When green they can be eaten like peas or edamame. Taste before harvesting! The green seeds should be sweet. (If they are chalky, it’s too late to harvest them fresh — best to let them ripen even longer and harvest when dry on the branch.) Gently pull the whole pod off the tree and place in a canvas or paper bag, bucket or basket.
Dry pods are beige and the seeds inside are brown. At this stage they are best eaten sprouted. Rather than picking by hand you can put a clean tarp on the ground and gently shake the dry pods off the tree. However, do not harvest dry pods/seeds off the bare ground.
PROCESS & STORE: Whether green or dry, Palo Verde seeds should be cleaned and processed for storage as soon as possible after picking to preserve freshness and reduce the chances of the pods moldering.
FRESH GREEN PODS/SEEDS should be blanched the day you pick them to prevent ripening or moldering. They can be blanched in the pod or shelled like peas and then blanched. To do this, wash your pods or seeds in cool water. Bring a pot of water to a boil. Meanwhile, prepare a large bowl of ice water. Add green seeds to boiling water and boil for at least 90 seconds. Remove, drain and immediately place seeds in ice water for 90 seconds. Once cooled, drain and package in labeled and dated plastic freezer bags, getting out as much air as possible.
DRY BROWN PODS/SEEDS are also best processed the day you pick, but can also be stored in an unsealed container outside until you do. Do not store in a plastic bag or they will molder! To process dry seeds, free them from the pod by hand or by laying them on a clean tarp, covering them with a clean sheet, and walking on it to crush the dry pods. Winnow out the pod, leaving just the dry dark brown seed. Freeze seeds for two days to prevent bruchid-beetle infestation. Store in the freezer until use or take them out, dry thoroughly and then store in a sealed jar.
EAT: Palo Verde flowers can be eaten raw in salads or candied for use in desserts.
Although they can be eaten raw, both green and dry/brown stages of seeds may be most easily digested when blanched, sprouted or cooked.
After blanching green pods, salt and eat the green Palo Verde seeds from the shell like edamame. Or use them in salads or soups, as garnish, or sauté or roast with seasoning.
Dry seeds are best eaten simply sprouted, or sprouted and then parched/roasted. To sprout: soak overnight and then rinse daily until seed coat splits open and sprout emerges. Remove sprouts by squeezing the split seed coat. Rinse with clean water and then use sprouts raw or lightly cooked. To parch/roast: Sprout seeds just until the tiny root emerges (1-2 days). Dry seeds in the sun, solar oven, or conventional oven set to 150 F. Once dry, put seeds in a dry skillet over medium heat to cook until seeds pop. Season with salt or other spices.
DOWNLOAD PRINTABLE POCKET GUIDE
Click to download the information from the section above as a PDF file: Palo Verde
(credits correction: URL for Bean Tree Farm is www.BeanTreeFarm.com)
PALO VERDE WORKSHOP INFO
Workshop Description: The Palo Verde workshop has been designed to be used in situations both with and without electricity and access to a computer. It is a hands-on workshop that teaches the basics of how to identify, harvest, and process Palo Verde seeds. It is recommended to be given in a situation where you can discuss the information and then go out when pods/seeds are ripe and actually harvest, giving participants hands-on experience with tasting and picking good pods. The season for this is usually late spring/early summer for green seeds and June for dry seeds, although this varies with elevation and yearly rainfall. However, if actual harvesting is not possible, the workshop can be given indoors or outdoors without the harvesting component.
This workshop begins with discussion about the importance of planting native trees in urban areas and using water-harvesting techniques to maintain these trees around one’s home and neighborhood. Participants then engage in activities to learn how to identify and differentiate between the two Palo Verde species, as well as how to harvest and process their seeds at home. They learn how to preserve seeds for long term storage and good ways to incorporate them into their meals.
This Workshop Kit Contains:
- Labeled jars with dry samples of Palo Verde seeds and pods, including samples of Foothills and Blue Palo Verde seeds and pods.
- A flash drive with:
- PowerPoint presentation with photos of basics of rainwater harvesting, Foothills and Blue Palo Verde trees; plant parts for identification; and processing and storage options,
- Palo Verde video,
- Workshop outline in Microsoft Word, and
- Instructions for gathering plant samples to bring to the workshop.
- Laminated color photos of all slides in the PowerPoint presentation.
- Palo Verde Pocket Guides as handouts.
- A copy of Eat Mesquite! A Cookbook, for display.
Other Desert Foods Workshops
Desert Harvesters offers workshops on harvesting, processing, and cooking with a variety of desert foods: Mesquite, Prickly Pear Fruit and Pads, Desert Ironwood, and Palo Verde. If you prefer a generalist approach, or need a workshop that is indoors and doesn’t include harvesting, we also offer a 2-hour Desert Foods Overview which combines the individual plant kits and offers a simple introduction to these plants and foods rather than in-depth explorations into each. Contact us for more information.
Need a Workshop Instructor? Hire a Desert Harvester!
Experienced harvesters are available to teach a workshop for your organization, business, or school. Please contact us for information on availability and fees.
Funds for this project were provided by the Urban and Community Forestry Financial Assistance Program administered through the State of Arizona Forestry Division – Urban and Community Forestry and the USDA Forest Service.