Orange Butterfly Weed has a deep-growing taproot, and it is much more finicky about the soil in which it prefers to grow. The most commonly available Butterfly Weed seed of this species is grown from populations originating east of the Mississippi and must be grown in sandy, low fertility, acidic soil. It will refuse to grown in heavier, compost-enriched loam, clay-loam, and clay soils. Mismatched soil is the most common reason gardeners have difficulty getting A. tuberosa to grow successfully.
Lauren Springer Ogden, renowned author, gardener, and landscape designer recommends that Orange Butterfly Weed be transplanted before the heat of summer (April-May) or in the fall. She has observed that the combination of wet roots and hot daytime temperatures favor root rot from soil pathogens. She also points out that this species is "highly soil-specific depending on the strain you grow". Lauren also relates that the plants are susceptible to pill bugs. "They will chew where the root meets the crown. And they love warm moist conditions". Another reason to not wait to plant in the heat of summer and not to mulch. This plant is happiest growing in bare, uncovered ground.
Orange Butterfly Weed is also sensitive to growing in damp soil, especially after transplanting. Yellow, chlorotic foliage is usually an indication of over-watering. I recommend that new transplants be watered thoroughly after the initial planting. After the initial watering, wait until the plant begins to wilt slightly before watering thoroughly again. Once you see new growth, a good soaking every 5 to 10 days will be sufficient. Once established, which happens in a few months, the plants may not need much additional water unless conditions are hot and dry. For those of us with drip systems, be sure to place the emitter off to the side of the planting hole so the roots won't sit in overly wet soil.