If you drove or walked the three-mile drive at the Minnesota Landscape Arboretum during late summer or fall in 2013, chances are you stopped for a visit at the Earth-Kind® hydrangea trial. Planted in the fall of 2010, this planting exploded with growth and bloom last year and it was hard to resist stopping for a walk through the beds.
During years 2-4, evaluation data is collected monthly on the 96 plants at each site. Data is collected on floral and foliar quality, plant size and habit, tolerance to environmental stresses (cold hardiness, drought tolerance, high soil pH, etc.), disease and insect tolerance, and the ability to perform well across a wide variety of soil conditions. Superior hydrangea cultivars that perform well across years and trial sites will be designated as Earth-Kind plants for their region so that gardeners and horticultural professionals know that these cultivars perform well with basic plant care.
Twenty-four hydrangea cultivars were planted in the trial. Fourteen of the cultivars are panicle hydrangeas (Hydrangea paniculata) and include First Editions® Great Star, First Editions® Tickled Pink®, First Editions® Vanilla Strawberry™, First Editions® White Diamonds®, 'Grandiflora' (also known as PeeGee), 'Limelight', 'Little Lamb', Little Lime™, 'PeeGee Compact', 'Pink Diamond', Pinky Winky™, Quick Fire®, 'Tardiva', and 'Unique'. Seven of the cultivars are smooth hydrangeas (H. arborescens) and include 'Anabelle', 'Bounty', Endless Summer® Bella Anna®, 'Hayes Starburst', Incrediball®, Invincebelle® Spirit and White Dome®. The remaining three cultivars are bigleaf hydrangeas (H. macrophylla) and include Endless Summer® Blushing Bride, Endless Summer® The Original, and Endless Summer® Twist-n-Shout®.
The Benefits of Earth-Kind®
Low input gardening and the identification of plant cultivars that thrive with minimal maintenance benefit gardeners and the environment. The use of genetically strong and well-adapted plants makes it much easier and more enjoyable for gardeners and landscapers to create and maintain beautiful landscapes. There is also a large reduction in labor and the cost of maintenance. Few plants need replacing if adapted and pest-tolerant cultivars are selected for use in a landscape. The use of these tolerant cultivars minimizes the amount of irrigation needed and the use of pesticides. Replenishing organic mulches can be labor intensive but the benefits to gardeners and plants far outweigh the added labor. Mulch provides weed control, reduces the need for irrigation by decreasing evaporation of water from soil, and buffers soil temperature to protect roots during the intense cold of winter and the heat of the growing season. As it decomposes mulch improves soil structure and creates healthier root environments for garden plants: nutrient- and water-holding capacity increase in sandy soils and soil porosity, water infiltration and drainage, oxygen levels, and root penetration improve in heavier clay soils. The health and appearance of plants improves as soil quality improves. Improved soil texture also goes a long way towards making the job of hand weeding a much easier task for gardeners.
As individuals, the impact of our landscape management practices on the environment may be very small but collectively we have an enormous and sometimes a negative impact. As we change our gardening practices, we can reduce or eliminate these negative impacts. Fertilizers and pesticides have the potential to decrease water quality if they move over impervious surfaces such as driveways and sidewalks and into our streams, rivers and lakes through storm sewer systems. As the use of these chemicals is reduced, so is the potential for them to reach the water bodies that we treasure so much in Minnesota. The use of water-wise practices such as drip irrigation and the selection of drought-tolerant plants help to conserve water resources in a time when climate change is creating longer and more frequent periods of drought that put additional demands on these diminishing water resources. The use of organic mulches improves soil quality and reduces the amount of yard waste entering landfills.
The benefits of low input landscape management practices have been documented in Texas where the Earth-Kind® program has been in existence for over 20 years. In gardens or communities where Earth-Kind® landscape management practices are practiced, there have been 50-70% water savings, a 98% reduction in the use of pesticides, and a 20% reduction of yard waste entering landfills. In Addison, TX where the parks & recreation department uses Earth-Kind® management, there was a 50% reduction in labor costs due to the reduced need for irrigation, weeding, fertilizers and pesticides, and replanting. The department saw a 70% reduction in water usage and lost the dubious honor of being the town's largest water consumer.
The effectiveness of the Earth-Kind® plant evaluation effort can also be seen in Texas. To date, 23 roses have been designated as Earth-Kind roses for the southern United States. These plants have high tolerances to pests and perform beautifully under harsh summer temperatures and drought conditions such as those seen in 2011 when Dallas set records for the most 100 degree days, highest daytime and night temperatures, and drought (3.6" of rainfall from March to August instead of the average 17").