Quality, Accuracy & Assurance - Verbinnen's Nursery

Native vs. Invasive Species

Did you know that much the American highbush cranberry (Viburnum opulus ssp. americanum / Viburnum trilobum) sold in the nursery trade is actually the non-native and invasive European highbush cranberry (Viburnum opulus spp. opulus)? While this can be an honest mistake, if care is not taken when harvesting seeds from seemingly wild plants, you could instead be helping an invasive species spread.

Image to the left: The subtle differences between the invasive European Highbush-cranberry (top) and the native and challenging-to-source American Highbush-cranberry (bottom)

As the American and European species can be difficult to distinguish easily, we take extra steps to ensure that we are only collecting and sourcing seed from pure, positively identified American highbush cranberry. In addition, as hybridization can occur when the two species grow in close proximity to each other, we also strive to harvest only from pure American highbush cranberry stands that are further isolated from non-native individuals. This requires an extra level of care, but we think it’s worth it.

Some other native species that we pay careful attention to that can also be mistaken for invasive species in the nursery trade include:

*(invasive species in brackets)

Speckled Alder – Alnus rugosa (Alnus glutinosa)
Paper Birch – Betula papyrifera (Betula pendula)
Butternut – Juglans cinerea (Juglans mandshurica ssp. sachalinensis & Juglans x bixbyi)
Tamarack – Larix laricina (Larix decidua & kaempferi)
American Red Raspberry – Rubus idaeus ssp. strigosus (Rubus idaeus ssp. idaeus)
Allegheny Blackberry – Rubus allegheniensis (Rubus bifrons)
American Pussy Willow – Salix discolor (Salix caprea)
Peachleaf and Black Willows – Salix amygdaloides & nigra (Salix alba, fragilis, xrubens)
American and Showy Mountain-ash – Sorbus americana & decora (Sorbus aucuparia)
Red Mulberry – Morus rubra (Morus alba, Morus alba x rubra) Not for sale, yet!!
Thin-leaved Snowberry – Symphoricarpos albus var. albus (Symphoricarpos albus var. laevigatus & Symphoricarpos occidentalis)

Amelanchiers

(& other tricky species!)

Did you know that there are 11 species of serviceberry (Amelanchier spp.) that are native to Ontario? Some species grow to only 1m tall while others exceed 15m. Some prefer sandy, acidic soils while others do well with clay, alkaline soils. Since they can be so difficult to distinguish from each other when young, most are sold in the nursery trade with incorrect labels, which creates uncertainty when planning for ultimate size and growing conditions. As serviceberries can only be positively identified at the flowering stage, we conduct early season flowering forecasts and surveys before deciding which plants to return to for seed harvest later in the summer. This ensures that the plants in our pots match the names on our labels.

Some other diverse groups of plants that require some extra care with proper identification include oaks (11 species native to Ontario), raspberries/brambles (14 species native to Ontario), willows (31 species native to Ontario) and hawthorns (39 species native to Ontario)

Image to the right: Forecasting future seed harvests from Smooth Serviceberry (Amelanchier laevis)

Willows

Did you know that willows (Salix spp.) are often grown from cuttings? While this can be a cost-effective way of growing these species, it results in cloned plants, which limits the amount of genetic diversity being distributed back into the landscape. Additionally, the stock plants used for producing the cuttings can often be of unknown origin, which may be far removed from suitability for our local region.

Genetically diverse populations in nature are critical for ensuring that plants can adapt to pest, diseases and environmental stresses. This is why we aim to grow as many of our willow species as possible from seed, all harvested from wild, documented Ontario populations. While this creates extra steps for us, it ensures that you get the most suitable, diverse and durable stock for your restoration projects.

Image to the left: Awaiting the ripening of Shining Willow (Sailx lucida) seed catkins.

Cottonwood

(Populus deltoides ssp. deltoides)

Did you know that pure eastern cottonwood (Populus deltoides ssp. deltoides) from southern Ontario is incredibly difficult to find available in nurseries? While pots can be labelled “cottonwood” or “Populus deltoides”, these plants are often produced from hybrid plants, such as Canada poplar (Populus x canadensis), non-natives like black poplar (Populus nigra) or the heavily distributed plains cottonwood (Populus deltoides ssp. monlifera), which has been introduced into southern Ontario. We carefully collect seed from true and regionally pure eastern cottonwood to ensure that you’re incorporating the proper species and genotypes into your planting projects.

Image to the right: Extracting seed from pure Eastern Cottonwood (Populus deltoides ssp. deltoides)

Images & information provided on this page is courtesy of Sean Fox