UNITED STATES—Spring, in several regards, is like autumn in reverse, or vice versa. Bloom increases for spring but decreases for autumn. Foliage increases for spring but decreases for autumn. The two seasons are in opposition. In this chaparral climate, the rainy season that began last autumn ends now. Irrigation that became redundant then becomes necessary now.

Diminishing rain is not the only reason that irrigation becomes more important for spring. Spring weather also becomes warmer and more arid, or less humid. Warmth and aridity increase evaporation of moisture that rain deposited not long ago. Increasing day length, intensifying sunlight and warmth accelerate plant growth. Such growth consumes water.

This need for moisture is progressive, though. Vegetation certainly requires more water as the weather becomes warmer and drier. However, it does not yet require as much as it will require later during summer. By then, the weather will be even warmer and drier, and the days will be even longer. Irrigation should increase accordingly in regard to weather.

Too much or not enough?

Unfortunately, there are no simple formulas to determine how much irrigation is needed. Some vegetation with shallow roots may require frequent but moderate irrigation. Some vegetation with deep roots may prefer less frequent but more copious irrigation. Rain is possible at any time. It can briefly interfere with the most efficient of irrigation schedules.

Soil also affects irrigation. Sandy soils drain efficiently, but do not retain much moisture. This may not be a problem for some species that tolerate occasionally dry soil. It may be more of a concern for species that prefer more regularly moist soil, though. Dense soils retain more moisture, but do not drain as efficiently. Soil amendments can improve soils.

Manual irrigation is easier to monitor than automated irrigation, but can be tedious. That is why most irrigation is automated nowadays. Automation is more likely to be excessive than insufficient. Desiccation, wilting and other symptoms of insufficiency of irrigation are obvious. Symptoms of saturation may not become obvious until too late for remediation.

Highlight: Saskatoon

Of 18 species that are native to North America, only two are native to California. Of these two, only one is native locally. However, some of the few nurseries that sell various saskatoons market them as native. Obviously, most are not. A few are hybrids. All of them are species of Amelanchier and are still rare here. Their common names are numerous.

Serviceberry, sarvisberry or sarvis may be some of the more common of names. Shadbush, shadwood or shadblow may be less common. Juneberry, chuckley pear, wild plum and sugarplum are likely regional names. They are more familiar where winters are cooler. Some sorts do not perform well locally because they prefer a bit more winter chill.

Saskatoons are locally popular primarily for their fruit, and only among a few enthusiasts. They are more available online than in nurseries. The fruits are pommes like tiny apples but are only the size of blueberries. They ripen to blackish purple for summer. Their early spring flowers are like wispy apple flowers. Most Saskatoons grow less than 10 feet tall. Some rarer types can grow thirty feet tall in favorable climates.

Tony Tomeo can be contacted at tonytomeo.com.