My grandad had this along his ditch which was really steep and un-mowable(sp?) He would just mow right up to the edge of it to keep it in the ditch. You'd occaisionally see some grass trying to grow through it, but it generally choked out everything else. God forbid you ever want to get rid of it once it establishes itself though. It's technically a tree and has a root system to match....
Heres some info....
Plant Taxonomy of Blue Rug Juniper Plants:
Plant
taxonomy classifies Blue Rug juniper plants under
Juniperus horizontalis. The
cultivar is 'Wiltonii.'
Plant Type:
These plants are low-growing
evergreen shrubs. Plants in the
Juniperus genus are considered to be
conifers, although, granted, most people would mistake the cones for berries. This mis-identification is perpetuated by the fact that you will often hear talk of these so-called "berries," which are used to flavor both cuisine and gin.
The plants are also
dioecious and considered to be one of the
creeping junipers.
USDA Plant Hardiness Zones for Blue Rug Juniper Plants:
This groundcover can be grown in
planting zones 3-9.
Characteristics of Blue Rug Juniper Plants:
Foliage is a silvery-blue, thus the first half of its common name. The second half comes from its growth habit, as it forms a dense, low mat (rug) -- making it an ideal groundcover. Height 4"-6", spread 5'-6'. Foliage turns a purplish-bronze in winter. Blue Rug spreads rapidly and is relatively resistant to some of the diseases that plague juniper shrubs. Incidentally, what look to be blue "berries" on junipers are technically cones.
Care for Blue Rug Juniper Plants:
No plant is "no-maintenance," but this one is certainly "low-maintenance." Groundcovers that flower require much more care. Space 4'-6' apart to form a dense enough mat to crowd out weeds. To aid their weed-control efforts prior to maturity, make sure they're well mulched (but don't pile up mulch over the plants' crowns). Don't allow fallen leaves and branches to smother young plants. Thin out mature plants for better air circulation, which well help avoid disease; but don't prune severely.
Sun and Soil Requirements for Blue Rug Juniper Plants:
Blue Rug juniper plants thrive in full sun and prefer well-drained soil with an
acidic pH. Before planting, prepare the ground with
soil amendments.
Uses for Blue Rug Juniper Plants:
In addition to their use as
groundcovers (see below), the juniper shrubs and their relatives make excellent specimens for a
rock garden design.
More on Blue Rug Juniper Plants and Similar Groundcovers:
There are numerous types of junipers, and they come in a variety of heights, forms, colors (golds, blues and greens) and textures. But note that not all junipers are suitable for groundcovers. Some junipers are trees, while others fit the more usual image of "shrubs," i.e., plants that stand anywhere from knee-high to chest-high. Such plants are suitable for privacy screens and hedges.
But the focus of this article is the vine-like, low-growing junipers. Where and why would you grow such plants? Although they can be grown on flat land, juniper groundcovers are most prized as plants that can cover a sunny slope, where they serve 3 purposes simultaneously: erosion control, weed control and eliminating the need to mow where footing is treacherous. In addition, many other plants find it difficult to thrive on sunny slopes, where water runs off so quickly that the vegetation is apt to go thirsty. But juniper, on the contrary, tends to be relatively
drought-tolerant ground cover and craves excellent drainage.
Many varieties besides Blue Rug juniper plants are suitable for groundcovers. A green cultivar of
Juniperus horizontalis, namely, 'Prince of Wales,' purportedly grows even more quickly, while another cultivar, 'Mother Lode,' bears greenish-gold foliage. Meanwhile, the 'Pancake' cultivar stays smaller than these, both in terms of height (an amazing 2"-3") and spread (2').
Other species of juniper groundcover are
Juniperus procumbens and
Juniperus squamata. The 'Blue Star' cultivar of the latter provides another option for those who seek that cool blue foliage. But
Blue Star juniper will get taller over time (up to 3') than Blue Rug and doesn't spread as much, proportionately (4').
http://landscaping.about.com/od/groundcovervines1/p/blue_juniper.htm
