Creeping Cedar

Creeping cedar (Juniperus horizontalis) is an uncommon plant throughout Minnesota, at least native populations of it. Cultivated varieties are quite abundant in a horticultural setting. Its distribution is quite interesting. It is very abundant in intact dune ecosystems, although these habitats are quite rare in the state. Otherwise it can be found on rock outcroppings, and along cliff and talus. These habitats are far more common, but creeping cedar is far less abundant here, completely absent from most of these locations. So, although it has a rather widespread distribution in a variety of habitat types it is still of heightened conservation concern. Similar to huckleberry in my last post, although always uncommon this plant used to be more abundant in the state. Thanks to fire suppression it has been in decline for quite a while. This plants relationship with fire is quite interesting, like its close relative eastern red cedar, it is an extremely fire intolerant species. It grows low to the grounds, has highly flammable oils, and does not resprout after fires. It also needs full sun at all stages of its life, and is easily outcompeted by other plants. When you look at its distribution with this context it starts to make a little more sense, habitats where it is abundant usually do not produce enough fuel to carry large fires. The wider lack of fire has allowed more trees and shrubs to enter these habitats that they were historically mostly absent from. Along the North Shore this plant is quite rare, I've only ever seen it at two locations: today at a seepy spot along the shore at Tettegauche and a few weeks ago on a dry rock outcropping overlooking Bean Lake. 

Creeping cedar (Juniperus horizontalis) along Superior's shore

State Special Concern Species

Creeping cedar on a rock outcropping overlooking Bean Lake 

Creeping cedar is not a cedar, but rather a juniper. In fact there are no cedars, or at least true cedars (genus Cedrus), in North America. Although there are many plants called cedar. There are three plants in the Juniperus genus in MN that all look quite similar. Creeping cedar looks like easter red cedar (Juniperus virginiana), although that species is a tree and creeping cedar rarely exceeds a few inches off the ground. Its growth habit is more similar to common juniper (Juniperus communis depressa), but the two have very different leaves. Another similar species is northern white cedar (Thuja occidentalis). Eastern red cedar is common in MN, but really not present along the North Shore, whereas the other species often grow associated with each other in the same habitat and might be mistaken for eachother. 

Creeping cedar has a low, creeping shrub-like growth form

Common juniper is often more upright, but can creep along the ground as well

Creeping juniper has scaly needles

Common juniper has very different needles

Young northern white cedar can also look similar with scaly needles, but they are flatter

A handful of other rare species were growing in this area not far from the creeping cedar. 

Blue blister lichen (Thalloidima sedifolium) usually grows on calcareous rocks, it is quite uncommon on the igneous rocks in this area

Rock speckled shield lichen (Punctelia stictica)

State Endangered Species

Hanging fringe lichen (Anaptychia crinalis)
State Special Concern Species

Ground frost lichen (Physconia muscigena)
State Watchlist Species - Insufficient Information