Wild Cucumber, Echinocystis lobata, is a member of the gourd (Cucurbitaceae) family.
Wild cucumber is a North American native considered to be an invasive alien species in PEI and NS.
The plant is very widespread on PEI, indicating that the plant was introduced many years ago.
It is unknown exactly how or why wild cucumber was introduced to PEI, but records indicate it as being introduced as an ornamental trellis-climbing plant.
Much of the information about this plant as an invasive species comes from Europe, where it is listed among the top 100 invasive species.
It continues to be spread by purchase as an ornamental climbing plant, as it has pretty leaves and interesting spiked fruits.
These fruits give wild cucumber its scientific name, Echinocystis lobata, which means hedgehog bladder.
Despite the name cucumber, the fruits are not edible to humans.
Produces highly branched, vine-like stems.
The stems are angled and hairless.
Leaves have 5 deep triangular lobes and a heart-shaped base.
The leaves of wild cucumber are nearly as wide as they are long and up to 18 cm across. with five star-shaped triangular lobes, resembling a maple leaf. The leaves have an alternate leaf arrangement and they have tiny widely spaced teeth around the edges.
Each leaf is paired with a long curly tendril used to cling to and climb other vegetation.
Flowers can be male or female.
Flowers have greenish white petals covered in short hairs.
Male flowers grow in clusters along long branching stalks.
Female flowers grow in solitude at the base of the long stem which bears the male flowers.
Flowers bloom from July to August.
Each node will have flowers.
Produces prickly, oval-shaped fruit which release the plant’s seed when it has reached maturity.
Fruit 5 cm long and, as mentioned earlier, they are not edible.
The seed pods are covered with sharp spines than burst open to disperse the seeds when ripe.
Each node will have a fruit.
A member of the gourd family, it requires moist soil and full sun.
What it does in the ecosystem
Wild cucumber grows along trails, in fields, on the edges of forests and in riparian zones across PEI.
It is an aggressive competitor for native plants, displacing them and competing for light, space, and nutrients.
Where native plants are displaced, local biodiversity is reduced.
Wild cucumber is a vine that grows on other shrubs and trees and can shade and choke out the plants it climbs up.
On PEI, this plant is predominantly a problem on stream banks and along hedgerows.
In an agricultural setting, the plant can cause issues with harvest and negatively impact crops.
The plant could cause issues in orchards if it climbs fruit trees.
Seeds may be distributed by birds and small mammals that use them as a food source.
Before selecting a control method, consider the size of the infestation, your available resources, and the amount of effort you are willing to expend.
Consider the local ecosystem and what other organisms or ecological processes may be affected by management.
As wild cucumber is a climbing plant, it is important to be wary of the other plants that it is climbing on. These plants may be seriously weakened, so treat them with care.
The plant spreads by seed, and flowers in June.
The ideal time for management is in the spring, before the plant grows to full size and starts to flower.
Plants can be managed by hand-pulling to remove the roots.
This is fairly easy to do but may be sped up by using a stirrup hoe to uproot the plants.
Remove the plant matter and set it aside in a dry area.
If the plants are large and long at the time of management (at least 60cm), they may be cut at ground level.
This cut will kill the plant’s aboveground parts and prevent it from going to seed.
It may be dangerous to try and pull down the vines. When pulled down, there is a chance they may bring branches or whole plants down along with them, creating a safety risk. Unless the vegetation they are climbing is suffering desperately from the excess weight of the vines, you can leave them in place to dry and die off.
It is a good idea to return to the site soon after management to ensure no new growth has appeared.
Mowing is another viable method of control in larger infestations, but one should be careful not to disperse the seeds.
Repeated mowing at regular intervals multiple times through the growing season is necessary to ensure eradication has been achieved.
This is because the plant will resprout after being mowed initially.
Chemical control methods exist for wild cucumber, but the PEIISC does not offer advice on chemical control measures at this time.
If using chemical controls, it is imperative that all local legislation and manufacturer’s instructions be followed during application.
DISPOSAL, REMEDIATION, AND SAFETY
Be careful not to prick your fingers on the sharp spines of the seed pod. Wear gloves when handling seed pods.
If managing Wild Cucumber after fruits (seed pods) have formed, it is recommended that you collect, bag, and properly dispose of all seed pods to prevent the release of seeds into the area.
Each time you manage the site, collect, bag, mark, and dispose of all plant parts properly.
Bag the seed pods in clear plastic bags.
Mark the bags boldly with a permanent marker. Write “INVASIVE PLANT” or “WILD CUCUMBER” on the bags.
Double bag the bags to prevent accidental dispersal later on and protect waste handlers from the sharp spines on the seed pods.
Tie the bags tightly and place them in your usual residential waste collection (THE BLACK BIN)
Never place invasive plants into the compost. This may allow them to become established once they reach the heap.
Clean and remove all plant parts from any equipment, clothing, or vehicles before leaving the site to prevent spread.
They can be picked off just like apples.
If you manage to remove the plant before it goes to seed, the plant parts can be left on-site to decompose.
As with most invasive plants, you will need to revisit the site year after year to remove any new growth that may arise.
Replant the area with native species to prevent the re-establishment of invasives and give any invasives that do reappear some competition.