Plant Of The Month

Picea omorika

It is important to consider what is seen in the winter garden for our region as the deciduous and perennials sleep through the cold for a solid four months. While ornamental grasses do their part to keep some interest in the landscape along with a variety of trees and shrubs lending unique branching or attractive bark, your eye still needs a little more to investigate. Volumes could (and have) been written about dwarf and weeping varieties of evergreen trees, but, for this month, we'd like to consider the straight species of a majestic needle leaf evergreen called the Serbian Spruce (Picea omorika).

Serbian Spruce has a limited native range existing on well-drained slopes mainly along the Drina River Valley, which forms the border between Serbia and Bosnia/Herzegovina. Native soils there are on top of limestone mountains giving a slightly higher pH than some evergreens would tolerate. Serbian Spruce occurs alongside of European Beech (Fagus sylvatica), Norway Spruce, (Picea abies), and Austrian Pine (Pinus nigra). The International Union for Conservation of Nature (IUCN) lists Picea omorika as endangered, partly due to many native stands being burned intentionally during the Bosnian War in the early 90's.

Unlike most spruce trees, the Serbian Spruce has a flattened needle more like hemlock than its Picea cousins. On the underside of the needles are two rows of very dense stomata (small holes that allow the leaf to breathe), which give a silver appearance to the underside of the branches. This two tone/bi-color effect is quite eye catching, lending a touch of elegance to the garden. Serbian spruce is also quite narrow compared to other spruce, usually reaching no further than about 10 feet from its trunk with upswept branches that show off the silver underside of the leaves. While the tree only puts on a moderate 12 inches of growth per year, with time it will touch close to 50 feet or more.

All too often we find landscapes with a Norway Spruce (Picea abies) planted 15 feet or less off the corner of a house to provide some sort of framing to the building. Norway Spruce is far too large for this setting, and perhaps if the desired effect is to provide a tall evergreen, one would be much safer in using the Serbian Spruce, as it is likely the most narrow you will find.

Most evergreen trees are often thought of as providing a backdrop to the other, showier plants in the landscape. A look at the cones of many spruce, especially Serbian, will tell a different story. Emerging early in summer, slightly less than 2 inches long, pendulous cones are a deep red/purple sometimes almost black. As they mature, the cones develop a strong cinnamon brown color providing a beautiful contrast to the shiny dark green needles. It is important to appreciate each plant in the landscape for its own unique beauty. While this tree may not have a beautiful flower to admire, it offers beautiful contrasting leaves, attractive cones, and an architecture that should be welcomed into the landscape.

Serbian Spruce is likely one of the most adaptable of the spruce. This tree can be found growing in full sun, though it seems to prefer a bit of shade in its day. In its native range, soils tend to have a higher pH but this can also be found happily growing in acidic soils. Pollution tolerance is observed to be high with this plant and perhaps could be considered for more use in an urban and commercial setting. We have seen reports that the tree does not tolerate harsh northern wind through winter, but have not personally observed this to be of concern. Perhaps some thought is warranted when placing in the landscape to provide some protection in winter.

You will find several cultivars of Serbian Spruce on the market. 'Nana' is a dwarf form reaching no larger than 5 feet by 5 feet maintaining a rounded habit. The leaves have the same bicolor effect and offer a softer texture than using a Mugo Pine or Bird's Nest Spruce. A second interesting cultivar found on the market is 'Pendula' which behaves similar to the species but only reaching half as high (25 feet) and usually slightly more narrow with heavily weeping branchlets off of tightly upward curved main stems.

The only pest that may give some issue is White Pine Weevil (Pissodes strobi), which can cause death of the leader as the larvae feed on the vascular tissues under the bark. You will know if this is an issue by the characteristic shepherds hook and brown needles. While rare on Serbian Spruce, should this become an issue, you must prune out the infested leader and destroy the debris. A new leader can be trained to take over. Cultural control of this pest is to keep White Pine away from other evergreens and proper pruning of infected leaders. A systemic insecticide can be used to reduce risk of killing non-target insects. Contact sprays can be difficult as the timing must be accurate and any larvae currently under the bark will be missed.

Consider this stately evergreen tree for either an accent plant or as a good member of a screen planting to add some texture and form interest. Planted where a Blue Colorado Spruce (Picea pungens f. Glauca) can offer some backdrop, the silver undersides of the Serbian Spruce really jump out and provide a beautiful companion planting.

Article by Jim and Shelley Funai. Jim Funai is full time faculty at Cuyahoga Community College, a PLANET accredited, associate of applied science in horticulture degree program, offering many paths to higher education to the green industry. Shelley Funai is a full time Senior Gardener at Stan Hywet Hall and Gardens in Akron, Ohio that offers a historic estate designed by Warren H. Manning and a beautiful manor house museum. Both are graduates of The Ohio State University. Contact Jim and Shelly via email at hortsquad@gmail.com.