H. citrina grows well in the spring and seems quite tolerant of frosts
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H. flava Major, a supposed variant of H. flava is an extremely good grow with tight light green foliage. H. flava Major seems to tolerate frost very well.
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H. hakuensis, suffers some tip damage in the spring do to frost but recovers and blooms fine.
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H. sempervirens is only marginally hardy in this climate does not do well. It has a spreading habit much like H . fulva is no where near as vigorous.
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