Agalinis purpurea prefers consistently moist soil, especially during its active growth phase. Water thoroughly when the top 2-3 cm of soil feels dry to the touch. Avoid waterlogged conditions, which can lead to root rot.

Reduce watering slightly in cooler months but do not allow the soil to dry out completely.

Pruning is generally not essential for Agalinis purpurea. Deadheading spent flowers can encourage a slightly longer bloom period and maintain a tidier appearance.

If the plant becomes leggy, light trimming in late spring can help promote bushier growth. Remove any dead or damaged foliage as needed.

Agalinis purpurea can be propagated by seed. Sow seeds in the fall or early spring. Scarification (lightly scratching the seed coat) can improve germination rates. Stratification (cold treatment) may also be beneficial.

It is a hemiparasitic plant, so successful germination and growth may require proximity to host plants.

Repotting is typically not a concern for Agalinis purpurea as it is often grown as an annual or short-lived perennial. If attempting to overwinter a potted specimen, repot in early spring before new growth begins.

Use a well-draining potting mix. Ensure the new pot is only slightly larger than the current one.