Legumes are easy to grow from seed - Tipuana tipu foliage and seed pods.
By Robin Y Rivet.
The virus pandemic is creating tight budgets, but more time to garden. Planting new trees should not be costly.
Think Seeds: If you’re rolling your eyes… Don’t. Many tree species germinate readily by seed, and typically grow rapidly. It is a premiere method that produces strong, climate-adapted seedlings. Consider that almost all plants reproduce sexually naturally. Eucalyptus are almost always grown from seed, and their pin-head size - belie their ultimate mature scale. A seed-grown eucalypt might soon shoot up 15 feet in a year, but you’ll need a magnifying glass and some tweezers to move the sprouted seed from a moistened paper towel - into a pot. Evergreens like loquats, oaks or poly-embryonic mangos are good examples of species where a seedling might have similar - or even superior qualities. Seed-grown trees improve vigor too, as replicative cloning can weaken genetics. Although many fruit trees will propagate by seed, most will have random characteristics – not a clone of the parent. However, chance seedlings account for many famous varieties of apples, peaches and avocados. And, if you do grow a seedling tree, it is yours to name - as it will be as unique as you are.
Volunteers: No time to plant seeds? Let wind and birds do it for you. Many tree species “self-sow”, and tiny seedlings emerge in-situ, so if you see a mature tree you like – go look around underneath it. Chances are good you might find a baby. Get a shovel and dig it out when it’s less than one foot, being careful not to cut off its long tender tap root. In my backyard, I’ve seen babies of tipu, jacaranda, carrotwood, evergreen elm, Chinese flame, loquat, sapote, guava, cherimoya and Aleppo pines.
Cuttings: Vegetative asexual propagation techniques are an excellent method of reproducing a ‘cultivar’. They maintain the unique characteristics of trees previously bred for appearance, color, taste, vigor or disease resistance. This works well for varietal pomegranates, figs, mulberries, and many ornamentals like crape myrtles or redbuds. All you need are clean pruners, potting medium and rooting hormone can be helpful, if not necessary.
· Soft-wood: flexible new green growth taken in spring before bloom; this roots very fast, often less than one month.
· Semi-hardwood: harvest early summer growth when green wood is beginning to show bark; these may take six weeks plus to root.
· Hardwood: older wood can take up to six months to root, and might need supplemental heat & humidity Start in lidded containers with sterile potting medium, and this works best when the scion is dormant.
Air-layering: The concept is simple. Force roots to form on an actively growing tree branch, accomplished by girdling a portion of bark and packing the skinned area with moistened moss, covered by a plastic or foil covering. Another method is burying a low live branch directly in soil, forcing it to make its own roots. Either can take a while, but are very effective to reproduce clones of evergreen, sub-tropical tree species.
Grafting:This technique is mired in mystery, but it is a simple process that most average gardeners can master. Proper timing and a few materials are helpful, but it’s really about patience and good eye-hand coordination. Line up the cambium layers from two cultivars of similar species and voilà – a new tree.
ISA Certified Arborist - Robin Rivet is an independent, consulting horticulturist & landscape designer. Robin currently serves on the executive committee for the San Diego Regional Urban Forests Council, was past manager of the Cool Communities Shade Tree Program, and appointed arborist for the City of San Diego’s Community Forest Advisory Board. In 2012, she helped launch a countywide tree-mapping website that calculated the ecosystem benefits of urban trees. This is her 25th year volunteering as a University of California Master Gardener, and she’s trained in utility and tree risk assessment. In 2013, Robin was selected as a fellow with the National Science Foundation’s “Art of Science Learning”, and in 2015 “La Mesa Beautiful” honored Robin as their “Citizen of the Year” for a decade of public service improving awareness of urban forestry. At her home in La Mesa, she helps tend a large backyard orchard and garden, and believes everyone should have components to mitigate climate change, supply edibles, provide wildlife habitat, and be water-efficient - as well as beautiful to the eye. She recently received a multi-media, digital arts certificate, with an ambition to create public educational environmental videos.