OAK COLLECTION
Why Oaks?
The Iowa Arboretum & Gardens has a rich history of growing and protecting oak trees. In fact, the first major collection established as part of the Arboretum’s mission was the Governor’s Oak Grove started in 1972. Oaks were selected as an important starting point for the Iowa Arboretum due to their abundance in the state, their importance for wildlife, and potential for ornamental landscape use. The state of Iowa had declared the oak as the state tree in 1961, and so the Arboretum chose to honor that designation by planting many throughout it’s decades of history. Out of the twelve species of oaks native to Iowa, five of them are native to Boone County and can be found across the Arboretum’s grounds: Quercus alba (white oak), Q. ellipsoidalis (Hill’s oak), Q. macrocarpa (bur oak), Q. muehlenbergii (Chinkapin oak), and Q. rubra (northern red oak). However, much of the existing oak collection is made up of nearly 100 individual swamp white oaks (Q. bicolor), another Iowa native.
Similar to many of the Arboretum’s other collections, an enthusiastic group of founders and early staff were the driving force of amassing so many unique oak trees. Al Ferguson, a volunteer horticulturist and his close friend Archie Sparks both collected oaks all across Iowa and planted them at the Arboretum. They had even started some hybridization work, crossing native oak species or collecting wild occuring hybrids. Later, Archie’s son Brian Sparks became a staff horticulturist and continued a legacy of oak planting. Finally, the Arboretum’s first executive director, Peter van der Linden, pushed for planting of all of Iowa’s native oaks and even published the Forest and Shade Trees of Iowa during his tenure.
To this day oaks are still being planted, many of which are native to North America, are wild occuring hybrids, or newly developed horticultural varities. Wild collections in the Arboretum’s own woodlands and offspring from existing oaks are also being selected for their landscape merits.
The Governor’s Oak Grove
With the first oak planting ceremony taking place in 1972 with Governor Robert D. Ray, the first major collections project at the Iowa Arboretum & Gardens was born, kickstarting Arbor Week celebrations in Iowa.
In 1971, Iowa’s Governor Ray sought to offer Iowans the opportunity to minimize environmental pressures in the landscape. An Environmental Action Program (EAP) was launched to encourage people to beautify, conserve, and become soil stewards of the Iowan landscape. Due to the interrelationship of these and other environmental programs, Governor Ray sponsored a similar program in 1972, which established the Governor’s Arbor Week segment of the EAP, and the ceremonial tree plantings that have occurred thereafter. Governor Robert D. Ray had the honor of planting the first Arbor Day, Governors’ Grove oak in 1972, which is a respectable, mature Scarlet Oak (Quercus coccinia) still living today.
Today nearly every past Iowa governor is honored in this grove. The lasting legacy of Iowa’s Arbor Week and Day live on in this grove, with additions to the collection happening still.
Several trees were lost to the 2020 derecho but trees to replace those lost have been planned to be planted in honor of the yet unrepresented governors. However, in light of the spread of Oak Wilt (Bretziella fagacearum) they will be planted a safe distance from the remainder of the grove.
Learn more about the Governor’s Oak Grove here.
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Plant List:
Quercus alba – White oak
Quercus alba x macrocarpa (x bebbiana) – Bebb’s oak
Quercus alba x robur (x bimundorum) ‘Prairie Stature’ – Prairie Stature oak
Quercus bicolor – Swamp white oak
Quercus bicolor x macrocarpa (x schuettei) – Schuette’s oak
Quercus bicolor x macrocarpa (x schuettei) ‘Epic’ – Epic oak
Quercus coccinea – Scarlet oak
Quercus dentata ‘Pinnatifida’ – Cutleaf emperor oak
Quercus gambelii x macrocarpa – Bur-gambel oak
Quercus imbricaria – Shingle oak
Quercus imbricaria x palustris (x exacta) – Hybrid oak
Quercus imbricaria x rubra (x runcinata) – Logue oak
Quercus macrocarpa – Bur oak
Quercus macrocarpa ‘Urban Pinnacle’ – Urban Pinnacle bur oak
Quercus montana x alba (x saulii) – Saul’s oak
Quercus muhlenbergii – Chinkapin oak
Quercus palustris – Pin oak
Quercus palustris ‘Green Pillar’ – Green Pillar pin oak
Quercus petraea ‘Muscaviensis’ – Columnar sessile oak
Quercus phellos – Willow oak
Quercus prinoides – Dwarf chinkapin oak
Quercus robur – English oak
Quercus robur ‘Fastigiata‘ x bicolor (x warei) ‘Kindred Spirit’ – Kindred Spirit oak
Quercus robur ‘Fastigiata’ x bicolor (x warei) ‘Regal Prince’ – Regal Prince oak
Quercus robur x macrocarpa (x macdanielii) – Macdaniel’s oak
Quercus rubra – Northern red oak
Quercus sinuata var. breviloba – Bigelow oak
Quercus velutina – Black oak