Horticultural Garden Notes: Collection Inventory, Fall Color and Hardy Larches, and Volunteers Power Through

Olga Bay larch with fall color on October 24

Olga Bay larch, Oct 24, 2018

Collection Inventory Field Check

Over the course of the fall, garden staff conducted an inventory field check for the approximately 4,000 accessioned plants in the Longenecker Horticultural Gardens living collection. The presence of each specimen was confirmed, map locations were verified for accuracy, and accession tags were located, checked, and made accessible. One hundred seven specimens were missing accession tags, and eighty-four lacked GPS coordinates. Continuing into the winter, GPS coordinates will be taken for specimens not previously mapped, and those missing accession tags will have new ones created and installed.  As in a museum, a verified and accurately mapped inventory is central to conserving the collection and ensures specimen accessibility for both staff and visitors. Inventory field checks will be planned at set time intervals and combined with formal plant evaluations such as plant health, height, and stem diameter.

Fall Color

Overall, fall color was lackluster this year due to unfavorable weather conditions, from an overly wet growing season to a cloudy and warm September. Trees did not develop the usual vibrant yellows and rich oranges and reds. Instead, many stayed green only to have their leaves freeze and fall after the temperature dropped to 22°F on October 21.

A few trees were undaunted by the weather and still lit up the Longenecker landscape. One was Larix gmelinii var. olgensis, known as the Olga Bay larch, native to Russia, China, and North Korea. This particular tree was grown from seed collected in Manchuria. It shone like a yellow beacon at the base of the pinetum, just south of the American chestnuts.

An anomaly among conifers, larches are deciduous and drop all their needles each fall and grow new ones the following spring. They are capable of outstanding yellow fall color. The Olga Bay larch is named for the Olga Bay in Vladivostok, Russia, where the first known botanical collection of the variety was made around 1930. It differs from the species in that its cones are slightly larger and its new shoots are coated with a dense orange-brown pubescence.

Larix gmelinii is known as the Dahurian larch and is the northernmost tree species in the world, growing on the tundra of Russia’s Taymyr Peninsula where it takes on a creeping prostrate form. It also has the ability to survive northeastern Siberian winters, the coldest on earth outside of Antarctica, with recorded temperatures as low as -90°F.¹ There are two Dahurian larches in the Longenecker Horticultural Gardens collection, derived from seed that was wild collected in China by the Beijing Academy of Forestry.

Volunteer Power

The record-breaking rain this year created continually saturated soils, pervasive weed seedlings, and excessively lush growth on many specimens. This, coupled with periodic flooding and an overabundance of mosquitos, made timely upkeep of the gardens more challenging than ever. And yet, with the help of volunteer coordinator Judy Kingsbury, the gardens were fortunate enough to host a record number of 258 individual volunteers who put in more than 1,200 hours keeping the gardens looking their best in spite of the weather. Ranging in age from middle schoolers to retirees, volunteers came from student and professional groups, 4H clubs, and Future Farmers of America, as well as individual plant enthusiasts. No matter their age or affiliation, all came with a can-do attitude and a desire to help. Many thanks to all who so graciously gave their time and energy to make the gardens a better place for all our visitors this year.

—David Stevens, Longenecker Horticultural Gardens curator


  1. “Northern Hemisphere: Lowest Temperature.” World Meteorological Organization’s World Weather & Climate Extremes Archive, wmo.asu.edu/content/northern-hemisphere-lowest-temperature.