Like many pine trees, Austrian pines do best if they are planted in fairly warm soil; late summer can be an ideal time to plant an Austrian pine. You can expect this pine to grow at a moderate rate of 12 to 18 inches per year in most circumstances. Be aware that this pine has some serious drawbacks for many regions of the country. It is extremely susceptible to the tip blight fungus Sphaeropsis (Diplodia)—so much so that planting the tree is strongly discouraged in many parts of the U.S. Even if you can avoid this serious problem, Austrian pine is prone to a variety of other disease and pest problems. Before planting an Austrian pine, consult your local University Extension Service to learn how well it grows in your region.
Light
This tree grows best in a location that receives full sun, but it can also tolerate a part-shade planting site, provided it gets at least four hours of sun daily.
Soil
The Austrian pine is able to grow in many different types of soil, especially ones that can be considered difficult, such as clay or sand. However, it thrives best in deep, moist soil that drains well. It has a better tolerance for alkaline soil than most pines.
Water
Water new trees regularly for the first year and during dry periods for the first three years. Once established, Austrian pines are fairly drought-tolerant.
Temperature and Humidity
This tree is well suited for USDA zones 4 to 7, hardy down to minus 25 degrees Fahrenheit. This is a species that prefers cool to cold temperate climates; in warmer, more humid climates it will be susceptible to more disease and pest problems.
Fertilizer
Feeding is not required for this tree. A 2- to 3-inch layer of mulch under the canopy will help provide slow-release nutrients and keep the soil moist and cool.
Types of Austrian Pine
There are several good cultivars available for Pinus nigra, including:
‘Austriaca’ : This variety has a stout growth habit with a broadly oval crown. ‘Pyramidalis’: This cultivar has a more pyramidal shape than the species tree, even as a mature specimen.‘Arnold Sentinel’: This is an upright, columnar-shaped tree that grows 20 to 24 feet tall, and 6 to 7 feet wide.‘Globosa’: This is a slow-growing, dwarf variety with a notably round shape. It will take 10 years to mature into a 1- to 5-foot specimen’Hornibrookiana’: This is a dwarf shrub variety, just 1 to 2 feet tall, with a spreading, mounding growth habit.‘Oregon Green’: This 20-foot specimen is prized for the white upright “candles” of new growth that appear in spring.
Pruning Austrian Pine
Little pruning is necessary, other than to remove dead or diseased branches. However, the branches tend to droop as the tree ages, so some pruning may be necessary to raise the canopy where the branches overhang sidewalks, driveways, or other living areas. Late winter or early spring is the best time to do this pruning, as the tree will be less susceptible to invasion by insects or fungi. This tree’s natural growth habit is to produce limbs all the way to ground level, so if you want clearance below the canopy, you’ll need to prune away the lower branches—which is best done in later winter or very early spring.
Propagating Austrian Pine
Pinus nigra, like most species in the genus, is difficult to propagate by vegetative means, so it is usually propagated by seed.
How to Grow Austrian Pine From Seed
Austrian pines are propagated by seeds found inside the cones. However, the seeds are slow to germinate and develop into saplings and can take as many as five years to grow in pots before they are suitable for landscape planting. Further, some of the named cultivars do not produce viable seeds, so this method works best for the native species. If you want to try seed propagation, here’s a method that works for most pines:
Potting and Repotting Austrian Pine
Dwarf cultivars of this slow-growing specimen can be grown in large pots, at least twice as wide and deep as the tree’s nursery container. A heavy clay pot is best, as it will resist tipping. Make sure the container has good drainage holes, and use a good-quality peat-based potting mix. Adding perlite or vermiculite will help the soil’s porosity. Plant the tree at the same height it was in its nursery container, tamping the soil firmly around the root ball to eliminate air pockets. Slowly water until the potting mix is fully saturated. A potted pine tree will need more frequent watering than an in-ground tree, And because nutrients leach out of the soil faster, a potted pine tree will appreciate a yearly small dose of slow-release fertilizer. Avoid heavy fertilizing, though, as this can make the tree grow too fast. Pine trees generally grow well with confined roots, so repotting won’t be a frequent task. When the tree finally does become root-bound, the best repotting strategy is to carefully remove it from the pot, trim back about one-third of its root mass, then repot in the same container using fresh potting mix.
Overwintering
Once they are mature, Austrian pines in the landscape will usually not require protection against winter cold if they are being grown within their established hardiness range. Young trees will benefit from a thick layer of dry mulch placed over the root zone for winter. If the fall has been dry, water thoroughly in the fall to prevent desiccation over the winter months. Potted Austrian pines must be moved to a sheltered location for the winter, such as a garage or shed. Another option is the bury the container in the ground up to the rim for the winter months. Left above ground and unprotected, a potted tree’s roots may die.
Common Pests and Plant Diseases
The Austrian pine is prey to many fungal diseases, such as lophodermium needle cast, diplodia (sphaeropsis) tip blight, as well as various wood rots and decays. Remove affected branches as you spot them. Spraying with fungicide may slow the spread, but once infected, it is hard to save a tree. Insect pests include the European pine sawfly, weevils, and Zimmerman pine moth. The tree is also frequently damaged by yellow-bellied sapsuckers feeding on the many insects that infest it. Spraying with horticultural oil may lessen insect damage, though this is difficult with a large established tree. The many problems with Austrian pine are so pronounced that the use of the tree is discouraged in many regions.
Common Problems With Austrian Pine
Aside from its susceptibility to pests and fungal diseases, Austrian pine can be susceptible to wind damage, especially in the winter if heavy snows weigh down the branches. Prune away dead branches as you spot them. With young trees, shake off heavy snow from the branches to reduce weight. Lacebark pine is hardy in zones 3 to 8 and grows fairly slowly to a maximum height of about 50 feet. It has attractive exfoliating bark that resembles that of a sycamore tree. Like Austrian pine, it does very well in urban conditions, but unlike Austrian pine, it has few serious diseases or insect problems. But be aware that the branches of lacebark pine can be a little brittle in regions that see heavy snow and ice.
