Sacramento Valley Elderberry Field Assessment
Key takeaways
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Blue elderberry seedlings yielded more and grew faster than American elderberry cultivars over the first two growing seasons
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Un-irrigated mature blue elderberry shrubs were highly productive but yield was variable. Genetic differences, spacing, water access, and many other factors interact.
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Main blue elderberry bloom on second-year plants began in mid-April and ended by late July, although occasional flowers persisted through September
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Harvest window for blue elderberries was mid June to late September, with a peak in early August. Yield peak timing in young plants may differ from un-irrigated mature shrubs.
- Good weed management, proper land preparation, and frequent irrigation may increase growth and yield over the first two growing seasons
This field demonstration focused on comparing blue elderberry and American elderberry for fruit production in Sacramento Valley hedgerows. Blue elderberry is native to the west coast and is currently most commonly planted for habitat, while American elderberry is native east of the Rockies and is more prominent in commercial fruit and flower production.
Goals
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Explore best establishment and management practices for elderberry in California hedgerows
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Assess potential mature yield of un-irrigated blue elderberry
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Assess harvest window and peak season for blue elderberry harvest
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Compare American elderberry to blue elderberry over first two growing seasons
Early growth and yield
We planted blue and American elderberries on three organic Yolo/Solano farms, then tracked their growth and yield for two growing seasons.
Farm A |
Farm B |
Farm C |
Strategies that may increase early growth and yield
Early growth is key: Increasing growth rate in year one appears to increase yields in year two. Choose management strategies that encourage wide, highly-branching growth with many basal shoots for maximum early per-tree yield.
Timing and tillage: Regardless of tillage strategy, fall is the best time to plant perennials in California, when soil softened by winter rains is easier for young roots to explore. For spring plantings, tillage may be especially important to help young roots to develop more quickly. Deep tillage may help deep and extensive root systems develop sooner if the planting site is compacted.
Irrigation: Weekly irrigation over the first two growing seasons may result in more extensive growth and higher early yield than less frequent irrigation, even with the same total quantity of water over the season.
Mulch and weed control: Using mulch is recommended for maintaining moisture, cooling and protecting soil, and controlling weeds. Weeds should be carefully controlled; special care should be taken during the first winter rainy season when young plants are dormant.
Tree protection tubes: If using tree protection tubes to prevent damage to young plants, remove them relatively early to encourage basal sprouting for maximum per-plant yield. Tubes can be removed as soon as the plants are growing vigorously, especially if leaves are pressing against the sides of the tubes. If tubes are left on, some early yield may be sacrificed as basal sprouts can be stunted or killed from extreme heat inside the tube.
Mature plant yields
We harvested the ripe berries from nine established shrubs of known ages in un-irrigated Yolo/Solano county hedgerows weekly for two summer harvest seasons (2018, 2019).
Management impacts on mature elderberry yield
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Variability: Average results suggest that mature yield may increase for 10 years after planting, but per plant yield was variable among shrubs of the same age in the same hedgerow. Genetic differences and many other factors are interacting.
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Spacing: Closer spacing appears to decrease per tree yield. The highest yielding shrubs were spaced at least 20-30 feet from the nearest large shrub or tree.
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Water availability: Proximity to nearby water sources may increase per plant yield and change the timing of fruiting for un-irrigated blue elderberries, due to their ability to scavenge for water.