Troubleshooting
Olympic Mullein problems — and how to fix them
Olympic Mullein (Verbascum olympicum) is generally forgiving once you match its basics, but a few issues come up again and again. Here is what each one looks like, why it happens, and the fix.
Crown rot
The most common cause of plant loss; waterlogged or compacted soil allows Phytophthora or Pythium to rot the crown — plant in raised, sharply drained positions and never allow water to pool around the rosette.
Mullein moth (Cucullia verbasci)
Striking yellow-and-black-spotted caterpillars feed on foliage and flowers from late spring; inspect plants regularly and remove by hand or apply Bt-based biological spray.
Failure to branch (single spike)
In very poor soils plants may produce a single unbranched spike rather than the typical candelabra; a light balanced feed in early spring of the flowering year and full sun exposure encourages the characteristic branching habit.
Prevent olympic mullein problems before they start
Most olympic mullein issues are care-mismatch, not bad luck. Dial in the basics:
Olympic Mullein problems — FAQ
Why is my olympic mullein crown rot?
The most common cause of plant loss; waterlogged or compacted soil allows Phytophthora or Pythium to rot the crown — plant in raised, sharply drained positions and never allow water to pool around the rosette.
Why is my olympic mullein mullein moth (cucullia verbasci)?
Striking yellow-and-black-spotted caterpillars feed on foliage and flowers from late spring; inspect plants regularly and remove by hand or apply Bt-based biological spray.
Why is my olympic mullein failure to branch (single spike)?
In very poor soils plants may produce a single unbranched spike rather than the typical candelabra; a light balanced feed in early spring of the flowering year and full sun exposure encourages the characteristic branching habit.