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Upcoming Events

Fourth Public Meeting - An Assessment of Native Seed Needs and Capacities

The public is invited to join this zoom session which will explore the roles of TNC staff from different state units in the native seed supply. Panelists will discuss their experience as users of native seeds and plants for restoration, and identify barriers to and opportunities for expanding their supply.

• Monday, February 22, from 3:00 - 4:15 pm Eastern

• Registration Information

Native Seed Stakeholder Meeting(s) 2021

Due to Covid-19, the 2021 meeting will consist of a series of online panel discussions and presentations, hopefully followed by an in person meeting later in the year. The first meeting will feature a panel of seed producers to discuss current topics in native seed production.

• When: Friday afternoons at 1-pm starting in mid-April

• Specific dates and more information will be coming soon!

Production Topic - Seed Cleaning

When producing foundation ecotype seed, the TPC’s goal is to provide pure, viable seed that retains the range of genetic diversity found in Iowa remnant prairies. We work to avoid unintentional selection at each production step, including seed cleaning. We regularly inspect each fraction of cleaning “trash” and, if needed, run it back through with adjusted settings to capture good seed that is either larger or smaller than average.

White meadowsweet, Spiraea alba, is a good example. We find abundant smaller, but filled and healthy-looking, seed in the aspiration fraction when air-screening this species. We are able to capture this material by adjusting the settings for a second (or third) pass.

We find that it’s challenging to separate Spiraea alba seed from small leaf fragments. This year, we found two tips that seem to improve the purity, though we haven’t had it tested yet:

1) We eliminated the brushing step since the dry capsules release nearly all seed if harvested at maturity, and this resulted in less fine “trash”

2) After air-screening, we ran the product through a set of soil sieves which provided a finer separation.

For more information on the importance of seed cleaning practices in maintaining genetic diversity of seed for restoration, see the article on Native Seed Cleaning and Testing in the special issue of Restoration Ecology devoted to Standards for Native Seeds in Ecological Restoration.

Species Spotlight

The TPC offers foundation seed of 3 ecotypes of false indigo bush, Amorpha fruticosa.

Photos: (bottom left) Flowering false indigo bush with eight-spotted forester moth; (top left) A silver spotted skipper caterpillar spun leaflets together with silk to make a protective nest; (bottom right) Bucket of clipped fruiting spikes, harvested on the early side (mid-September); there is little shattering risk, so we now wait until pods are more uniformly brown before harvesting; (top right) Pod with oil glands, beetle hole, and bruchid beetles; we find beetles during cleaning, but seed losses seem minimal.

• Range – Native across much of U.S. but considered invasive in some northeastern and northwestern states.

• Applications – Commonly found in wet soils, but has a broad range of soil moisture tolerances. Can form thickets up to ten feet tall and might be effective as a living snow fence. Blooms mid-June and is visited by diverse bees, moths, and butterflies. Leaves are host to silver-spotted skipper larvae.

• Production – Shrub that flowers and sets seed on second year wood. Seed production varies from year to year, but plants are long-lived and need little maintenance. Irrigation appears to improve production. Yield estimates (based on production rows from 480 to 800 square feet in area) were nearly 900 pounds/acre in a peak year for an irrigated row compared to 200-360 pounds/acre for unirrigated plots.

• Harvest – Probably possible to combine harvest, but I haven’t been willing to risk wear and tear on our plot combine from cutting and threshing woody material with finger-thick stems. We hand-harvest in late September through late October. There is little risk of shattering. Use gloves to strip pods from stems into a bucket or clip fruiting spikes.

• Cleaning – False indigo bush seeds are enclosed in a tough pod (like lead plant pod but slightly larger) with prominent oil glands, visible even to the unaided eye. Brush the harvested material using beater bars, spread on a tarp, and use a fan to help the sticky oils evaporate for a few days before further cleaning.

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