Milkweed is the larval food of the Monarch butterfly which is endangered in Nova Scotia. It is of valuable to know where patches of it are located to inspect during the breeding season for larva and eggs. These early stages of the Monarch can then be protected from predators and reared to increase the butterfly population. Two species of milkweed are growing in Nova Scotia.  Swamp milkweed (asclepias incarnata) tends to be found in wetter environments and Common milkweed (Asclepias syriaca) grows well in the light soils of the Annapolis Valley and is known to be growing in several places. The Common milkweed is invasive because it spread by a robust root system as well as its air-born seeds. Large patches of it can occur in abandoned unused fields but most patches are small with less than 50 plants.

Below is a Google map of  known locations of Common Milkweed.(created Nov 2015 and updates as patchs are found or destroyed)   Locations have been added and corrected with the help of members of the Blomidon Naturalists Society and others interested in the well-being of the Monarch butterfly. The icon (leaves) marks locations on the map where the milkweed has been found. Most of the larger milkweed sites are in the Waterville-Cambridge-Coldbrook area. More exists but is still to be located.  If you know of other plots not show, please share to be added on the map:  info@valleynature.ca

Note: Click on the icon for a brief description.  Zoom in to locate the site more accurately on the map.If your browser doesn't show, here is the  map on Google Maps
 

 You can help by just driving, walking, or biking you local area and reporting any milkweed you observe growing there. In the Fall, milkweed has very identifiable seed pods to help recognize the plants. If you do find some plots, we would like to know. The following is the desired information

1. location (so it can be monitored next summer for Monarchs)
2. type of milkweed
3. size of the patch
4. short description of the habitat it is growing in and growing next to.
5. your name and contact information

Milkweed will next be visible in May when it will be sprouting up from the ground. It will be flowering in June-July.
After flowering in July, Common Milkweed slowly grows seed pods that are characteristic of milkweed. The size and shape of leaves are the best key for identifying the plant at this stage.
In late summer, autumn and winter, Common Milkweed can be identified easily from the opening pods of seeds with the fluffy seed parachutes.

Wikipedia has a good description on its  Common Milkweed Page.  This is the most abundant type of milkweed and grows in patches because is spreads through an expanding root system. It can fill whole fields, usually fallow or abandoned fields. It is common along hedgerows and along roadsides and especially along the railbed that runs through the centre of the Annapolis Valley. It likes light soils and thus is abundant in the Cambridge and Waterville areas. In the Fall and Winter the milkweed plants can be easily identified from the prominent seed pods and seed fluff that may be still be attached to the pods. The stalks are tough remain after the leaves drop after a frost.

There is also a Wikipedia Swamp Milkweed page.

Swamp milkweed will grow in wetter soils and is usually associated with headwaters of streams or their intervales.  It is seen more commonly on the South Mountain and less so in the Valley. However, it can grow anywhere. It is a tall plant but has smaller leaves than the Common milkweed.

Maps of Kings County

Here is a  historical note from Klaus Jensen who lives north of Coldbrook on Brooklyn Street about Common Milkweed:
"The first recorded occurrence was in 1929 (I think) near the Avonport  train station. That year some national botanical organization took a train trip from Halifax to do some botanizing in the Valley and the finding was recorded in The Canadian Field Naturalist.  In the late ‘80’s or early ‘90’s the Nova Scotia Department of Agriculture’s weed inspectors conducted a milkweed survey of Kings County, and as I recall,  some 347 locations were found.  The distribution of milkweed at that time was clearly associated with the east/west railroad line and was likely introduced in grain shipments.  At that time, milkweed was on the noxious weed list and and there was considerable effort to keep it in check by spraying it.  Herbicides were never successful in eradicating it from any location although milkweed could be suppressed.  This program ended at least 15 years ago.  Since then stands of milkweed have greatly increased and new stands are popping up in many places."

In the botianical book "Flora of Nova Scotia" by Roland and Smith (1969 N.S. Museum)

"Ascleplias syriaca (Common Milkweed)

          Sparingly introduced as a weed in light soil; at scattered places in the Annapolis Valley; at Le Breau's Creek in Hants Co.; and near Mabou in CB; presumabley being introduced also elsewhere. Scattered throughout the Maritime Provinces. July"