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Cultivar Close-up: Hi-Yo Silver!

Q. robur 'Argentomarginata'

As we celebrate 25 years of the IOS, we take a look at oaks that have an association with silver. In a Species Spotlight Joeri Strijk describes Quercus argentata (the epithet derives from the Latin word for silver: argentum) and below are three well-known cultivars with silver associations.

Species Spotlight: Quercus argentata Korth.

Quercus argentata

Quercus argentata is an evergreen tropical oak native to the islands of Borneo (absent in Brunei), Sumatra, and Western Java, as well as to Peninsular Malaysia.

Species Spotlight: Quercus ithaburensis Decne.

Quercus ithaburensis

Quercus ithaburensis Decne. is a deciduous oak species native to the East Mediterranean basin. 

leaf_comparison.jpg

A naturally occurring hybrid, widely adopted by the nursery trade in the form of cultivars, labors under a misnomer: there is precious little Hispanic about Quercus ×hispanica

Cultivar Close-up: Quercus ×bebbiana 'Taco'

Quercus xbebbiana Taco

Found in the late 1980s by Guy Sternberg in Springfield, Illinois, this selection was noted early on for its rapid growth rate and strong central leader. 

Cultivar Close-up: Quercus robur 'Timuki'

Timuki

This cultivar was selected by Raimond Cinovskis, from the Botanical Garden of the Academy of Sciences, Salapils, Latvia and was introduced by Silva Tarouca Research Institute for Landscape and Ornamental Gardening, Průhonice, Czech Republic.

Hybrid Highlight: Quercus ×heterophylla F. Michx.

 Quercus-x-heterophylla_6-Andreas Gomolka

Named in honor of one of America’s first botanists, John Bartram, Quercus ×heterophylla is known by many as Bartram’s oak.

Species Spotlight: Quercus ilicifolia Wangenh.

leaf_r_43_m.jpg

Quercus ilicifolia is a little oak with a big name: bear oak. 

Species Spotlight: Quercus crassifolia Bonpl.

Quercus crassifolia is tree ranging in height from 4 to 15 meters, and is usually easily recognized by its leaves: stiff and leathery, glossy blackish green above, covered with a layer of pale brown hairs beneath, and with bristle-tipped teeth above the widest part of the leaf.

Species Spotlight: Quercus rotundifolia Lam.

qrotundi_var_avellanae.jpg

A Mediterranean oak with a long-standing relationship with humanity.

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Editor's Picks

The story behind acorn snacks enjoyed on IOS Tours last year
Editorial Staff | Jun 27, 2025
Group photo at Guthrie-Smith Arboretum
Four days exploring oaks on the east coast of North Island
Website Editor | Jun 21, 2025
Catalpa destroyed by tornado
Many trees have been lost due to an intense storm on May 15
Guy Sternberg | May 26, 2025

Plant Focus

Acorn of Quercus carduchorum
A rare species from the Zagros forests in Iran

Plant Focus

Cultivar Close-up: Hi-Yo Silver!

Q. robur 'Argentomarginata'

As we celebrate 25 years of the IOS, we take a look at oaks that have an association with silver. In a Species Spotlight Joeri Strijk describes Quercus argentata (the epithet derives from the Latin word for silver: argentum) and below are three well-known cultivars with silver associations.

Species Spotlight: Quercus argentata Korth.

Quercus argentata

Quercus argentata is an evergreen tropical oak native to the islands of Borneo (absent in Brunei), Sumatra, and Western Java, as well as to Peninsular Malaysia.

Species Spotlight: Quercus ithaburensis Decne.

Quercus ithaburensis

Quercus ithaburensis Decne. is a deciduous oak species native to the East Mediterranean basin. 

leaf_comparison.jpg

A naturally occurring hybrid, widely adopted by the nursery trade in the form of cultivars, labors under a misnomer: there is precious little Hispanic about Quercus ×hispanica

Cultivar Close-up: Quercus ×bebbiana 'Taco'

Quercus xbebbiana Taco

Found in the late 1980s by Guy Sternberg in Springfield, Illinois, this selection was noted early on for its rapid growth rate and strong central leader. 

Cultivar Close-up: Quercus robur 'Timuki'

Timuki

This cultivar was selected by Raimond Cinovskis, from the Botanical Garden of the Academy of Sciences, Salapils, Latvia and was introduced by Silva Tarouca Research Institute for Landscape and Ornamental Gardening, Průhonice, Czech Republic.

Hybrid Highlight: Quercus ×heterophylla F. Michx.

 Quercus-x-heterophylla_6-Andreas Gomolka

Named in honor of one of America’s first botanists, John Bartram, Quercus ×heterophylla is known by many as Bartram’s oak.

Species Spotlight: Quercus ilicifolia Wangenh.

leaf_r_43_m.jpg

Quercus ilicifolia is a little oak with a big name: bear oak. 

Species Spotlight: Quercus crassifolia Bonpl.

Quercus crassifolia is tree ranging in height from 4 to 15 meters, and is usually easily recognized by its leaves: stiff and leathery, glossy blackish green above, covered with a layer of pale brown hairs beneath, and with bristle-tipped teeth above the widest part of the leaf.

Species Spotlight: Quercus rotundifolia Lam.

qrotundi_var_avellanae.jpg

A Mediterranean oak with a long-standing relationship with humanity.

Pages

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