Penstemon (Beardtongue) in Zone 4a & 4b

Penstemon digitalis

When to plant penstemon (beardtongue) in zone 4b

Zones 4a and 4b share the same average frost dates in our data, so this page covers both.

Method: Direct sow: Direct-sow outside. Penstemon (Beardtongue) doesn't transplant well, or doesn't need the extra time indoors.

Start indoors	Not typically started indoors
Direct sow / transplant outside	Apr 17–Apr 24
Estimated bloom	Apr 16 '28–Apr 23 '28 (First real harvest the season after planting)

Spacing: 1 per square foot (square-foot-gardening spacing). Mature height: 2-4 ft.

Penstemon digitalis is a tough North American native that flowers in early summer and asks for very little.

How penstemon (beardtongue) fits zone 4's season

Zone 4b's frost-free window runs about 128 days, from May 15 to September 20. Penstemon (Beardtongue) takes about 1 growing season to reach full flowering, so what matters here is how many of these seasons it gets, not whether one is long enough.

Penstemon (Beardtongue) is hardy in zones 3-8, so in zone 4b it stays in the ground through winter and comes back rather than being replanted. Allow about 1.75 ft of spread at maturity.

Good companions

No standout companions recorded yet for Penstemon (Beardtongue).

Where to buy penstemon seeds

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