The Sun (San Bernardino)

Mulch covers it for avocado grower; ornamental­s and perennials, too

- Please send questions, comments, and photos to joshua@perfectpla­nts. com. For more informatio­n about area plants and gardens, go to Joshua Siskin's website, thesmarter­gardener.com.

If you plan to grow avocados or even if you are already growing them, I highly recommend visiting the website of Greg Alder (gregalder. com). It would appear to be the definitive site for backyard avocado growers.

The site includes Alder’s experience­s growing a large variety of fruit and vegetable crops, yet one customary gardening practice is barely mentioned. That practice is fertilizat­ion.

Alder makes a statement that many would consider astonishin­g. In all his years of growing avocados, he has never fertilized a single tree. Never. I remember working in avocado grove management in Temecula many years ago. Temecula is not far from Fallbrook, a locale considered the epicenter of avocado growing in California. In any event, I remember providing one fertilizer or another to the trees, applied through a drip irrigation system, no less than twice a month.

“I’ve never applied fertilizer­s to any of my trees because they’ve never told me they’ve needed anything more than the deep mulch of wood chips,” Alder relates.

“As for how much organic matter to add to the surface under your avocado tree, that’s hard to calculate with any precision. I personally don’t even try. My approach is to merely make sure that the soil is always covered. As soon as the mulch layer thins out, I add more materials. But for my first applicatio­n under a tree, I put it down about a foot in depth.

Alder also writes that you will need to use less mulch as time goes by, saying it won’t be used up as quickly after a while.

“Keep a layer at least 2 inches thick of wood chips under the tree at all times,” Alder advises. “This protects and feeds the worms and microbial creatures in the soil below, which in turn protect and feed the tree’s roots. With this mulch, it’s very possible that you will not need any additional fertilizer.”

Alder writes that the layer where the mulch and soil meet will start to resemble forest soil after a few years if you keep it covered.

He also cites the BneiDror experiment conducted in Israel. “Fuerte avocado trees were given chemical fertilizer or composted animal manure, and results were observed

Richly composted soil nurtures self-sowers like annual delphinium and opium poppies.

Spuria irises flower with gusto in a Reseda garden.

Iceland poppies and other ornamental­s benefit from a layer of mulch.

This patch of ivy geraniums and the orange version of yellow bells thrives on a street corner in Sherman Oaks.

for 10 years. The trees given composted manure grew more slowly but produced an average of 50% more avocados.”

If decomposin­g organic

matter is sufficient for fertilizat­ion of fruit trees, how much more so is this true regarding the vast majority of ornamental plants, which by contrast are light feeders. Let’s say you live in a condominiu­m complex with lots of large trees that need regular pruning. As long as you recycle your tree trimmings as mulch around your ornamental shrubs and perennials, you will never need to fertilize them.

In Loren Zeldin’s Reseda garden, among the hundreds of rose and iris varieties that he cultures to perfection, two self-sowing annuals are happily growing together. One is annual delphinum (Consolida ajacis), also known as larkspur, and the other is opium poppy (Papaver somniferum). The larkspur is showing off long wands of purple blooms, while the large, spherical poppy infloresce­nces are pink and red. Most of Zeldin’s irises are the bearded kind (Iris germanica), but he also has a flourishin­g patch of the more understate­d spuria type (Iris spuria).

Iceland poppies (Papaver nudicaule) are also flowering now and will self-sow given richly composted soil. Meanwhile, California poppies (Eschscholz­ia californic­a) are displaying their vivid blooms and, by removing them as they fade, you will be rewarded with another wave of silky orange flowers.

Every plant has its moment, and the moment for fortnight lilies, also known as Moraea (Dietes species) or butterfly iris, is now. Most of the year, this species is nothing but a collection of stiff, narrow, nondescrip­t evergreen leaves. But then suddenly you are transporte­d to a dreamy place where butterflie­s, conjured up by Moraea’s flowers, reign supreme.

There is a simple yet brilliant display of color at Tyrone Avenue and Moorpark Street in Sherman Oaks. The orange version of yellow bells (Tecoma stans), which flowers throughout the year, is underplant­ed to cherry red ivy geraniums (Pelargoniu­m peltatum), another virtually nonstop bloomer.

•••

There is a Mother’s Day Weekend Show and Sale of the Geranium Society from 9 a.m.-4 p.m. May 7-8 in Ayers Hall at the Los Angeles County Arboretum, 301 N. Baldwin Ave., in Arcadia. The show is free with arboretum admission. Tickets must be purchased at arboretum.org.

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PHOTOS BY JOSHUA SISKIN
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