About Honeysuckles in Manitoba

About Honeysuckles in Manitoba

By Linda Dietrick, Master Gardener

About 15 species of plants called honeysuckles are hardy enough to grow in Manitoba. The fact that they share a common name, however, masks some major differences among them. Several honeysuckles have shown themselves to be seriously invasive and should not be included in our gardens, while others are perfectly harmless or even beneficial. To help you sort out which species are worth planting and which are not, here’s an overview.

Invasive shrub honeysuckles

 

Let’s begin with the “bad guys”: four non-native shrub honeysuckles in the genus Lonicera (pronounced lon-ISS-er-uh): Amur (L. maackii), Morrow’s (L. morrowii), Tatarian (L.tatarica), and bella, also called Bell’s (L. xbella, a cross between L. morrowii and L. tatarica). Introduced from Asia and Europe, these species and the one hybrid have been used as ornamentals in North America since the 1800s. Their hardiness, attractive foliage, characteristic red, pink, or white blooms, and bright red berries made them popular. By the 1920s, however, it was already evident they were expanding beyond their original sites into natural areas, and they are now a real problem.

They grow rapidly and produce abundant berries that are attractive to birds, which then distribute the seeds. The resulting plants take over the understory of woodlands and outcompete native vegetation, which in turn reduces habitat for native insects and birds. This invasive behaviour has been recognized in most northeastern US states, including Minnesota, Wisconsin, New York, and Maine, where the non-native honeysuckles are on state invasive plant lists and in many cases regulated by law. Ontario also has infestations, including in Zone 4 northwest Ontario. Although invasive honeysuckles are still not listed on any provincial or federal weed lists in Canada, the Ontario Invasive Plant Council and the Canadian Coalition for Invasive Plant Regulation regard them as priority species for control, removal, and regulation in the marketplace.

 

In Manitoba, we are not exempt, especially as our climate warms. Photos on www.iNaturalist.org document the presence of invasive Lonicera species in natural areas across our region, from Pinawa Dam Provincial Park through the Whiteshell and into Lake of the Woods and northwest Ontario. Of particular concern is Tatarian honeysuckle, which, owing to its origins in Central Asia and Siberia, is extremely cold-tolerant (for photos, see: www.invasive.org/browse/subthumb.cfm?sub=3043). The Tatarian honeysuckle cultivar ‘Arnold Red’ is still sold by several Manitoba nurseries. ‘Bella Dropmore’ honeysuckle, a hardy pink-flowered cultivar of L. x bella, was bred by Frank L. Skinner and likely offered in his Roblin nursery up to the 1960s. If these or any of the other invasive honeysuckle shrubs listed are still growing in your garden, please remove them, and don’t add any more.

 

For now, an exception can probably be made for another exotic that is on some invasive lists in the US Northeast and Midwest: European fly honeysuckle (L. xylosteum and its hybrid with L. tatarica, L. xylosteoides). Sold for their compact, mounding foliage and said to flower rarely, cultivars include L. xylosteum ‘Emerald Mound’ and L. xylosteoides ‘Clavey’s Dwarf’ and ‘Miniglobe’. The latter, a Morden Research Station introduction from 1981, is still widely sold. If you have any of these, consider removing them, or at least ensure they don’t produce berries and seeds.

 

Now for the honeysuckles that are no problem at all. They include two hardy ornamental vines, the honeysuckle better known as haskap, our native Lonicera species (some of which might be garden-worthy), and the bush honeysuckles, which are North American native plants that actually belong to the genus Diervilla.

Vines

 

Frank Skinner’s most famous plant introduction (1950) was L. x brownii ‘Dropmore Scarlet Trumpet’ honeysuckle vine, now grown all over the world. As he explained in his book Horticultural Horizons (pp. 27, 46, 92), it was a cross between two North American natives: hairy honeysuckle (L. hirsuta), which he collected in northern Minnesota, and trumpet honeysuckle (L. sempervirens) from the southeastern US. It has considerable hybrid vigour and hardiness and is attractive to hummingbirds. Another honeysuckle vine with tangerine flowers, ‘Mandarin’ (sometimes called Mandarin Trumpet) is a cross between ‘Dropmore Scarlet Trumpet’ and a Chinese species, L. tragophylla. It was developed at UBC and introduced in 2003. Both vines are good candidates for sunny spots in Manitoba gardens. On the other hand, don’t be tempted by Japanese honeysuckle vine (L. japonica), a highly invasive Zone 4 species that has spread throughout eastern North America.

Haskap

Haskap used to be known as sweetberry honeysuckle and is indeed a Lonicera species. Bob Bors, who developed many of the available cultivars of L. caerulea var. edulis in the University Saskatchewan’s Fruit Program, wants everyone to call it haskap, the name given to it by the Ainu people of Hokkaido, Japan, who first discovered the berry centuries ago. Highly nutritious and early to ripen, it is not invasive and deservedly popular.

Native Lonicera species

 

In Manitoba, there are five indigenous species of Lonicera: Canada fly honeysuckle (L. canadensis); glaucous, limber or twining honeysuckle (L. dioica); bracted, involucrate, or black twinberry honeysuckle (L. involucrata); swamp fly honeysuckle (L. oblongifolia); and mountain fly honeysuckle (L. villosa). According to Manitoba Conservation, all but Canada fly honeysuckle are fairly common in the province, and photos suggest that the glaucous and bracted or black twinberry honeysuckles might be worthwhile additions to gardens. Both are woodland shrubs, the former with showy yellow and orange flowers, the latter with yellow flowers in pairs, each enclosed in a dark red bract. According to Gardening@USask, bracted honeysuckle is already valued in Europe as a garden plant. Native plant nurseries might take note.

Diervilla or bush honeysuckle

 

Finally, there is another shrub native to Manitoba called (northern) bush honeysuckle, Diervilla lonicera. Pronounced deer-VILL-uh, it is named for the Frenchman who brought it back to Europe from Canada around 1700. Its small yellow flowers resemble those of the Lonicera species, hence the common name. It’s low-growing (< 80 cm) and bushy and tolerates both shade and dry soil, so I have found it makes a good ground cover under trees. It will sucker, but the side shoots can easily be dug and given away to friends. Native bees use its flowers, and it’s host to the snowberry clearwing moth.

 

Plant breeders have turned to the Diervilla genus to develop a range of new, non-invasive honeysuckles for the nursery trade. For example, the native plant company American Beauties offers a selection of D. loniceracalled ‘Copper’ with reddish new growth. Under the trade name Cool Splash^®, First Editions offers a variegated, Zone 3-hardy mutation of the southern bush honeysuckle D. sessilifolia, which is native to the US South.

 

 

 

Going further, plant companies have crossed D. lonicera with D. sessilifolia to produce hybrids known collectively as Diervilla x splendens. Protected by patents, these plants have cultivar names that are often just letters and numbers. They are sold under trade names meant to catch the eye of the consumer. Proven Winners offers the Kodiak^® series of D. splendens, including Kodiak Red 2.0, Orange, Black, Jet Black, Fresh, and Spiced^®. They each feature a different shade of foliage and apparently don’t sucker as much as the parent plants. Similarly, Bloomin’ Easy offers bush honeysuckles in two colours: dark red Nightglow^® and amber Firefly^®.

 

Gardeners who wish to support clearwing moths are advised that caterpillars will not feed on foliage with red tones because of the chemicals (anthocyanins) that cause the pigmentation. In general, though, the new Diervillas are attractive options for Manitoba gardens.

References

Bors, Bob, and Sara Williams. “Haskap.” Growing Fruit in Northern Gardens. Coteau Books, 2017, pp. 196-205.

Canadian Coalition for Invasive Plant Regulation (CCIPR). “Reducing the Sales of Invasive Plants in Canada.” Online white paper, 2024. ccipr.ca/wp-content/uploads/2024/04/CCIPR-Reducing-Sales-of-Invasive-Plants-040424.pdf.

EDDMapS (Early Detection and Distribution Mapping System). Species Information for Lonicera. www.eddmaps.org/species/.

Gardening at USask. “Bracted Honeysuckle (Lonicera involucrata).” Online article dated May 3, 2021. gardening.usask.ca/articles-and-lists/articles-plant-descriptions/native-plants/bracted-honeysuckle.php.

Green, P. S. “Identification of the Species and Hybrids of the Lonicera tatarica Complex.” Journal of the Arnold Arboretum 47.1 (Jan. 1966): 75-88.

Manitoba Conservation Data Centre Plant List. www.gov.mb.ca/nrnd/fish-wildlife/cdc/pubs/plant_list_mbcdc_2024jan.pdf.

Ontario Invasive Plant Council. “Invasive Honeysuckles (Lonicera spp.): Best Management Practices in Ontario.” Downloadable brochure. www.ontarioinvasiveplants.ca/invasive-plants/species/invasive-honeysuckles/.

Skinner, Frank L. Horticultural Horizons: Plant Breeding and Introduction at Dropmore, Manitoba. Manitoba Dept. of Agriculture and Conservation, 1967.

FEATURED PHOTO: ‘Dropmore Scarlet Trumpet’ honeysuckle vine
Photo by Matt Lavin via Wikimedia Commons, CC BY-SA