Tag alder (
Alnus serrulata) grows as either a small tree or a large shrub. In the arboretum collection, we have one large shrub. It's growing in a very wet location, in partial shade. It would perhaps prefer more light.
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| The tag alder (Alnus serrulata) is worth an extra look this week: reproductive cones and catkins are mixed in with the remaining summer foliage. You can find the arboretum's tag alder shrub along the drainage channel, between the Student Union Building and Hamilton Hall. This shrub is more than 25 years old. In November of 1993, these plants were collected from Cypress Lake in Bossier Parish, and they were planted in the ground of the arboretum the following month. |
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| From left to right: tag alder leaf, new cones, old cones, and male catkin |
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| Tag alders are deciduous. In Louisiana, during late October, summer foliage remains on the shrub, available for your inspection. The leaves show some signs of yellowing. |
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| Tag alders have simple, alternate leaves. |
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| Tag alder leaves have an ovate shape with serrated, wavy margins. |
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| Small clusters of fresh green cones can be found on the tag alder this week, and for several weeks to come. |
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| These cones are the female reproductive structure. |
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| Dried-out female cones from last year persist on the shrub. |
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| Also, they resemble tiny pine cones. |
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| The fresh green catkins are the male reproductive structures. They are still developing, and we do not expect them to bloom any time soon. |
Please consult the following online sources for more information about this species:
Louisiana Plant Identification and Interactive Virtual Tours (LSU AgCenter)
NC State Extension
Virginia Tech Dendrology
United States Department of Agriculture
