Some of these plants came with European settlers as beloved reminders of home. Others were contaminants of crop seed. And as long as humans have been traveling between the continents, plants have gone with them. Some introductions are intended for agriculture, some for medicinal reasons, and many for ornamental purposes.

The following ornamentals, while not listed on the Alberta Weed Control Act's designated weed list, have escaped intentional plantings and invaded natural areas. A few have even become pests of urban areas, much like the dandelion.

Creeping bellflower - (Campanula rapunculoides) like it's name implies, this creeping rooted perennial gets around by sneaking under fences, even sidewalks. It also reproduces by seed. The blue flowers lie along one side of the stem. Leaves are opposite and lower parts of stems have a reddish color. Creeping bellflower is resistant to 2,4-D herbicides.

Baby's Breath - (Gypsophila paniculata) Baby’s Breath is an ornamental perennial introduced from Europe in the late 1800’s. In winter the stems break off and are blown about by the wind - just like tumbleweeds. Seed is then spread to pastures, agricultural fields & natural areas where new infestations grow. It is now widespread across Canada and the northern United States. The Fort MacLeod area has large patches infesting fields & pastures, and the Crowsnest Pass also has a few patches.

Caragana - (Caragana arborescens) aka Siberian Peashrub This shrub was introduced to North America to help preserve topsoil during the erosion of the1930's. Able to establish quickly in poor soils, Caragana can quickly turn into a 'living' fence. Old homestead plantings remain and have begun to invade & crowd out native poplar stands. Caragana reproduces by seed only and therefore can be controlled by cutting before flowering.

Dame's Rocket - (Hesperis matronalis) native to Eurasia and introduced to North America in the 1600's. This member of the mustard family is a prolific seed producer that often end up in 'wildflower' mixes. Flower color can be magenta through to pink or white. Dame's rocket is often confused with garden phlox...Dame's rocket has 4 petals & alternate leaves...Phlox has 5 petals & opposite leaves. Dame's rocket has escaped intentional plantings in Waterton Lakes National Park and also in the Crowsnest Pass.

Himalayan Balsam - (Impatiens glandulifera) aka Policeman's Helmet, Poor Man's Orchid, Indian balsam. Himalayan Balsam is native to India and the Himalayas, and was introduced as a garden ornamental in the 19th Century. The flower resembles a British policeman's hat, hence one of the common names. This fast growing annual can reach an impressive size over the growing season, rapidly out-competing other plants. The leaves occur in whorls around the stems and the plant prefers moist areas. The seed capsules are very brittle and explode upon contact. Since this plant has a shallow root system it can be controlled by hand-pulling.

Maltese Cross - (Lychnis chalcedonica) aka Jerusalem Cross. Maltese Cross is a native of Russia and Siberia and was an early import to the American colonies. The flowers are generally scarlet red, but white flowers also occur. The stems are hairy, leaves occur opposite. It has escaped flowerbeds and moving up an undisturbed slope behind the village in Waterton Lakes National Park.

Queen Anne's Lace - (Daucus carota) aka Wild Carrot. Introduced from Europe, this plant is the genetic source of today's edible carrots. It is a biennial that reproduces by seed. Notice the dark center of the flower – English lore say’s this came from Queen Anne pricking her finger while stitching lace and shed a drop of blood. Known as wild carrot is the US, this has become a serious problem plant on rangelands.

Russian Olive - (Elaeagnus angustifolia) Russian olive is a Eurasian import (1930’s – probably as an ornamental and to stabilize soil) that can grow to about 30 feet. It is fast growing and favoured as a windbreak tree. It thrives is poor soils because it can fix its own nitrogen. It will grow in dry soils but does best in sandy riparian areas. Admired for it's silvery foliage, Russian olive produces large amounts of leaf litter. Autumn olive (E. umbellata) produces red berries and has spread across the eastern US and Russian olive the west, southern BC and southeastern Alberta.

Salt-Cedar - (Tamarix spp) aka Tamarisk, eight species of salt-cedar were introduced into the United States from Asia in the 1800’s. Three of these species became invasive. At least 3 species of Tamarix were sold in 1854 for windbreaks, creating shade, soil stabilization, and ornamental shrubs. It was first reported out of cultivation in the 1870’s and the greatest degree of invasion occurred between 1935 and 1955. By 2001 it reached the Canadian border.
Salt-cedar is a deciduous shrub/small tree that grows most successfully along riparian (creeks/rivers, ponds) areas. Its roots extend deeply into the soil to access the groundwater. These trees can consume as much as 200 gallons of water per day. Where groundwater is not present Salt-cedar sends out lateral roots to access other sources of water.
Salt-cedar occurs from below sea level to more than 7,000 feet (2,134 m) in elevation & are remarkably tolerant to stress conditions...some species have been observed to to grow 3-4 metres in a single season. It’s scale-like leaves remove salt from the atmosphere which is then released into the soil – the increased salinity in the soil makes it unsuitable for many native plants and shrubs.
Salt-cedar, like many other invasive plant species, has a great reproductive capability. A mature salt-cedar plant can produce 600,000 seeds annually, and has the ability to flower during its first year. Seeds are easily dispersed by wind and water, and severed stems and shoots of salt-cedar readily root in moist soil.

Teasel - (Dipsacus fullonum) Teasel was introduced from Europe possibly as early as the 1700’s. Its spiky seed-head's original use was for raising the nap of cloth. In the last 20 to 30 years teasel has spread from Quebec & Maine to Ontario & Michigan, and then south to North Carolina, Tennessee and Missouri.

It is used now as an ornamental, especially for dried flower arrangements.
A single teasel plant can produce over 2,000 seeds and the immature heads of cut-leaved teasel are capable of producing viable seed. Young plants produce a tap root that can grow over 2 feet long.

Wildflower seed mixes - Grossly misnamed, "Wildflower" mixes very often contain the seed of non-native plants that have been legislated as invasive by multitudes of agencies across North America. The contents of these mixes is rarely listed on the container, and the wide variety of common names used for some plants only adds confusion.

Do not purchase these seed mixes unless the contents are listed on the package and do not contain the seed of invasive ornamentals.

Following is a list of non-native plants with both common name/s and their scientific name that often appear in so-called wildflower mixes:

Dame's Rocket - see above, Baby's Breath - see above, Maltese Cross - see above
Toadflax - Yellow Linaria vulgaris or Dalmatian Linaria dalmatica; spurred snapdragon, butter 'n eggs

Oxeye Daisy - Chrysanthemum leucanthemum

Wild Caraway - (Carum carvi) This is the same caraway available in the grocery stores. Not native to North America, caraway has been a spice crop in western Canada for many years. However this plant has escaped cultivation and proven to be extremely invasive & persistent - completing displacing native forbs & grasses. It is not grazed by wildlife or livestock. A member of the carrot family, it's finely divided leaves are hard to notice until this biennial begins flowering the nest season. Seed-heads are extremely brittle and fall apart upon contact.

Yellow Clematis - (Clematis tangutica) This spreading vine plant is a cultivar from Europe with yellow, pendant flowers. Seeds have silky, long tufts that are easily carried on wind & water. Many nurseries warn that it is an aggressive plant once established. Both urban & natural area infestations are becoming more common around Calgary and westward out to the mountain Parks.

So what can you do?

- You can find out about the potential invasiveness of plant by simply doing an internet search...especially with the Latin name of the plant. If it is a problem somewhere you'll likely find some information and whether it is hardy in your growing zone.

- Do not purchase or grow ornamental invasive plants and encourage your friends & neighbours to do the same.

- Remove invasive ornamentals from your yard and dispose of them in a landfill - do not compost invasive plant material.

- Don't transplant plants from ditches, vacant land & natural areas unless you know what they are. Many of the most invasive plants are mistaken to be 'pretty wildflowers.'

- Do not let invasive plants go to seed.

- Try to use regional native plants...they are already suited to your environment.

- Help out locally to prevent the introduction of invasive plants and control current infestations.

Everyone can be part of the solution!