Forsythia × intermedia 'Karl Sax'
Karl Sax Border Forsythia

 Plant Type:
 Hardiness:
 Deciduous / Evergreen:
 Flowers:
Yellow (Lovely, 4-petaled bright yellow flowers (1.25-1.5" across) held horizonally on branches; early to mid spring)
 Foliage:
Green (Summer foliage); Yellow (Generally poor yellow-green to purple tinged in the fall)
 Fruit:
Brown (Capsule; not ornamentally important)
 Ultimate Height:
7-8 feet
 Ultimate Spread:
7-8 feet
 Soil:
Quite adaptable to soil type
 Diagnostic Characteristics:
Leaves (3-5" long by 1.5-2.5" wide) are opposite, simple, and entire near base and toothed near tip. Flowers form in leaf axils. Multiple buds at nodes. Four-sided, greenish-brown stems having chambered pith and solid pith at nodes (Forsythia suspensa has hollow internodes).

Additional Information

The Karl Sax Border Forsythia is a dense shrub that bears its dark yellow flowers horizontally. Flower buds are more cold hardy than many Forsythia variants, but flower buds can be killed by severe winters in zone 5, and frequently in colder zones. Plants, however, are hardy in Zone 4. Cut stems excised in mid-winter will flower indoors due to very short chilling requirement. Too big for most foundations and small border plantings (Don't Shear!). Remove old wood for best appearance.

1 Forsythia × intermedia 'Karl Sax' found

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= Heritage plant = Memorial plant
Number Accession ID Location
12009_01029*APGM

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