Monday, June 30, 2014

A Tree Race--the Acorn & the Potted Tree (Grimm’s “The Tortoise & the Hare” revisited)

Justin Evertson

We’ve been monitoring a small oak-growing study in Waverly the last few years designed to evaluate nursery growing methods of bur oaks.  Bur oaks were planted from three different growing methods: traditional smooth container, fabric grow bags and direct seeding of acorns collected from oaks growing on the UNL campus. The acorns were planted in fall 2011. Nursery trees planted Fall 2012. Care has been minimal, but the trees were watered during exceedingly dry summer of 2012 and again in 2013. Observations so far:

Plastic Container Trees: Started about 1.5” caliper and 10’ tall. They were all pot-bound, with severe root circling in the container. The roots were not cut or squared at planting time. Significant dieback has occurred on all three plants and the root systems are not yet well-anchored. One is completely dead, the other two are re-sprouting from low on the trunk and would likely not be acceptable to the typical tree buyer.

Grow Bag Trees: Started about 1” caliper and 7’ tall. There was minimal root-circling at planting time. The roots were not cut or pulled out at planting time. There was some dieback from the 2012 drought though not nearly as bad as the plastic container trees. All three root systems appear to be well-anchored now.  All trees are putting out good growth this spring and are finally starting to be taller than when they were planted.

Acorn Seeding: There are six trees total (after thinning six batches of seedlings in late 2012). All have grown quite well. Care included rabbit fencing the first two years and occasional watering during the 2012 drought. Four of the trees are already over 5’ tall and two are over 6’ tall (averaging over 3’/year the last two years). The trees are well branched with strong vertical growth.

Conclusion: Plant the acorns if you can! After this year, it is almost guaranteed that the acorn grown trees will all be taller and more resilient (better established roots) than the nursery grown trees. However, the grow-bag trees are clearly superior to the plastic-container grown trees in this study. Considering that they had to survive the terrible heat and drought of 2012, they have done fairly well and would probably be acceptable to the typical tree buyer/planter.

So far, this study confirms the importance of a good root system for establishing young trees. At the end of the 5th year of growth, most trees will be dug up and roots will be closely examined.
PHOTOS from top: grow-bag roots; plastic container roots; planting site.

Tuesday, June 24, 2014

Vines: The “Incredibles” of the Garden

Lemon lace vine (Fallopia)
Christina Hoyt
        Vines are much like superheroes. They have a notorious reputation and seem to gather either fan clubs or mobs with weed whackers wherever they ramble. We hate them for their uncontrolled behavior, yet love them for their ability to conquer the aesthetic evil in our gardens. They go where no shrub goes, shimmying up walls and defying harsh elements, protecting slopes from erosion and softening structures. There are a few vines whose superhero tendencies should be unleashed with caution (Virginia Creeper, Trumpet Vine, Boston Ivy) and other vines are outright noxious, the Kudzu of the south, and shouldn’t be messed with.
        How do we know what vine to plant?  No one would call in Superman to defend Gothenburg, nor would anyone expect to see Spiderman flying through the night. Nor should anyone ask clematis to scale a wall without support or Virginia creeper to stay in a nice tidy corner. Vines are created differently, and have specific characteristics that make them work for different tasks.
Only clinging vines, vines that grow with the assistance of adhesive disks or adventitious roots, can scale walls or smooth surfaces. They have small sticky pads that hold the vine to the surface and allow it to climb. Clinging vines tend to be some of the more aggressive vines. For example, Boston Ivy (Parthenocissus tricuspidata) can scale three stories, growing out of compacted soil, and continue to grow about three feet a year! English Ivy (Hedera Helix), an evergreen, and the native Virginia Creeper (Parthenocissus quinquefloia) are other examples.  On rough surfaces plants like the elegant but slow-growing climbing hydrangea (Hydrangea petiolaris) sprout roots from the stem and hold the plant to the surface.
Chocolate vine (Akebia) with spring blossoms
         Vines that do best on poles, arbors or trellises climb by one of two methods:  either twining (the plant twists itself around the object) or by tendrils, little finger-like appendages that attach to the surface.  Most vines fall into one of these categories, giving an array of options to the gardener. Twining climbers like bittersweet (Celastrus scandens), wisteria (Wisteria spp.) and trumpet honeysuckle (Lonicera sempervirens) work well on poles or arbors. For arbors and trellises, the best choices are vines that climb mostly by the means of tendrils like the more aggressive grape vine (Vitis spp), lemon lace vine (Fallopia aubertii ‘lemon Lace’), chocolate vine (Akebia quinata) or the less aggressive clematis.
         With all of the possibilities, it is important you check the vine’s credentials to make sure it will work for your site: how it climbs, how aggressive it is, how much support it needs and what it needs in terms of sun, moisture and type of soil.  Any reputable nursery will be able to help you choose.  So next time you have aesthetic evils lurking in your garden, don’t forget to call in the vines! 

Tuesday, June 17, 2014

Time for Pie—Native Juneberry/Serviceberry Similar to Blueberries

Karma Larsen
       If you’re fortunate enough to have Juneberries on your property or nearby, and quick enough to beat the birds to them, now’s the time to enjoy this wonderful native tree/shrub. Juneberry or serviceberry (Amelanchier species) have fruits similar to blueberries, and they’re just as nutritious and appropriate for eating fresh, on cereal, in pies or smoothies. 
        According to the Montana State University Extension guide, they’re actually “higher in protein, fat, fiber, calcium, magnesium and manganese than blueberries and strawberries.” 
        Fortunately they’re just as appealing and and adaptable for landscape use. Three of the 25 species of Amelanchier in the Northern Hemisphere are native to the state of Nebraska:

  • Saskatoon serviceberry (Amelanchier alnifolia) is native to the central and northern portions of the state and grows about 15’ high.
  • Shadblow serviceberry (A. arborea) usually grows into a multi-stemmed understory tree and is common along the banks of the Missouri River.
  • Dwarf serviceberry (A. sanguinea) is native to northwestern Nebraska and grows about 10’ in height.
  • There’s also a wide range of cultivars, including Amelanchier alnifolia ‘Regent’ that grows to just 4-5’ in height and spread, small enough for even the most constrained yard.

        So grow some trees and shrubs and eat them too!