Swift Current Creek
Invasive Plant Species Control Program

Dame's Rocket
(Hesperis matronalis)
Alternate names:
Sweet Rocket, Dame Rocket, Dame's Violet, Mother-of-the-evening

Origin:
Dame's Rocket is native to Eurasia, but was introduced to North America in the 1600's. Because it is not native to our area and quickly takes over landscapes, it is considered an invasive alien species. It was introduced to North America as an ornamental plant, and is sold in many garden centers as a perennial and in many "wildflower" seed mixes.

Habitat:
Moist woodlands, woodland edges, roadsides, open areas and especially riparian areas.

Photo credit: Debbie Nordstrom

Interesting Facts
- Each plant can produce up to 20,000 seeds!

- Dame's Rocket blooms from June to early July, and has very fragrant flowers. Its growing season is much longer than most native plants, putting it at an advantage.

- This plant starts out as a basal plant (growing near to the ground) in its first year of growth, then shoots up the next spring to produce flowering stems.

Did you know...
In the City of Swift Current, Dame's Rocket has been found along the Swift Current Creek. This has likely happened because seeds of plants in residents' gardens have been washed into storm sewers and discharged into the creek.

Many of the suspected Purple Loosestrife sites that were phoned in to the Saskatchewan Purple Loosestrife Hotline were actually Dame's Rocket; for example, many sites have been spotted along the Swift Current Creek. Because of its invasive nature, as much care has to be given with Dame's Rocket as Purple Loosestrife.

Purple Loosestrife Infestation
Photo credit: Linda Haugen
USDA Forest Service
Bugwood.org


Purple Loosestrife Flowers
Photo credit: Norman E. Rees
USDA Agricultural Research Service
Bugwood.org

Dame's Rocket crowds out desirable native plants. This changes the structure of riparian ecosystems, and changes their ability to function properly (filtering out contaminants, stopping soil erosion, slowing water flow, and providing wildlife habitat). When riparian areas are not able to do these functions, this causes deteriorated water quality.

What does Dame's Rocket Look Like?
(Click on photos to enlarge)

Photo credit: Debbie Nordstrom

Flower head:
- 4 petals per flower
- Unopened flowers at top
- Flowers may also be pink or white

Photo credit: C.Pyle
USDA-NRCS

Basal rosette
(First year juvenile plant)

Photo credit: Angela Salzl

Stem:
- Hairy stem
- Leaf attached directly to stem
- Hairy leaves
- Finely toothed leaf edges
- Leaves alternate on stem

Photo credit: Angela Salzl

Cylindrical seed pods
(Mature plant)

Management and Control Options:
- Avoid "wildflower" seed mixes because many of them contain invasive plant seeds. Be sure you know exactly what is in wildflower mixes before purchasing!

- In large infestations: Clip off plants with pruning shears near the ground when plants are in full bloom. Do not pull these, because pulling causes soil disturbance, which results in more seed germination, doubling the number of seedlings in established communities!

- In small infestations (less than 100 plants per 10 square meters): Pull the entire plant, bag it and take it to your landfill to rot, or burn it. Do not let the plant dry before attempting to burn, as the seedpods may still burst open and spread the seeds. You may compost the plant if it has not started flowering yet.

- Burn infested areas that are only at the seedling and rosette stage, if there is sufficient leaf litter to act as fuel.

- Mow large infestations during peak bloom (before seed set). This will deplete the seedbank in the soil.

Chemical Control:
- Selectively spot-apply glyphosate herbicides (such as Roundup) in late fall when the native plants are dormant, but the Dame's Rocket basal rosette leaves are green and vulnerable to spray. Apply selectively to avoid other plants and watercourses. Hand wands and wicking are ideal to use.

Integrated Pest Management in Large Sites:
- This uses multiple methods to be more effective and reduces risk of populations becoming resistant to individual methods of control, and controls the plants at different growth stages.
- Combine mowing or clipping and applying herbicide to the rosettes in the fall to elminate the seed production and deplete the seedbank.

REMEMBER: All control measures must be repeated annually to eliminate the seedbank in the soil!

Garden Alternatives for The Green Thumb:
- Blazing star (Liatris)

- Speedwell (Veronica longifolia)

- Monkshood (Acontium napellus)

- Delphinium spp.

- False spirea (Astilbe arendsii)

- Lupine (Lupinus)

- Lobelia (Lobelia cardinalis)

- Salvia (Salvia superba)

- Fireweed (Epilobium angustifolium)

- Giant hyssop (Agastache foeniculum)

- Pink bee-plant (Cleome serrulata)

- Garden lily (Lilium spp.)

- Western wild bergamot (Monarda fistulosa)

- Bee balm

- Garden phlox (Phlox paniculata)
Copyright © Swift Current Creek Watershed Stewards 2019


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