Answer: Polemonium (Jacob's ladder) is hardy zones 3-8 so you should have better success than you've been having! Jacob's ladder prefers part shade (full sun only where summers are cool), and cool, moist, rich, well-drained soil (with a pH level of 5.0 to 8.0). Plant seedlings in the early spring, or in the early autumn and top-dress with manure or leaf mold. Water plants during dry spells and cut back stems to the ground after flowering. My sources tell me that flowering will be inhibited by hot weather.
Next time you plant Jacob's ladder, amend the soil with organic matter before planting, and mulch over the root area to help the soil retain moisture.
Hope this helps!
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