Butterfly bush (Buddleia) care: invasive status by state and how to grow responsibly

Standard Buddleja davidii is a declared noxious weed in Oregon and Washington. In those states and beyond, sterile cultivars like the Lo & Behold series are the responsible choice -- and they perform well.

Before we get into how to grow butterfly bush, we need to talk about where you live.

Buddleja davidii — the common butterfly bush — has been declared a noxious weed in Oregon and Washington state, where it has escaped gardens and colonized roadsides, riverbanks, and disturbed areas. Per Missouri Botanical Garden, it "has escaped gardens and naturalized in the eastern U.S. plus Washington, Oregon, California and Hawaii." Per Oregon State Extension, Buddleja davidii is specifically named as an invasive plant that "spreads by means of seeds" and requires aggressive deadheading management.

If you are in Oregon or Washington, the guidance is simple: plant only certified sterile cultivars, or choose a different plant entirely. The good news is that sterile alternatives exist and perform well.

I don't grow butterfly bush at my Long Island yard. The deer pressure is moderate-to-high here, and butterfly bush makes the approved plant list for deer-resistant shrubs. But my south-facing yard runs full afternoon sun, and I've had enough plant projects competing for attention that I haven't added this one. The guide below is built from Missouri Botanical Garden, NC State Extension Plant Toolbox, Penn State Extension's invasive species context, and Oregon State Extension.

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The invasive status question

Per Missouri Botanical Garden, standard B. davidii has been "declared a noxious weed in Oregon and Washington" and "aggressive spreading has been observed in a number of eastern states including Pennsylvania, New Jersey, West Virginia, Kentucky and North Carolina."

Per Oregon State Extension: if you grow a plant that "spreads by means of seeds, such as purple butterfly bush (Buddleia davidii), aggressively deadhead the plant. Be sure to remove the spent flowers well before seeds have time to mature."

Per Oregon State Extension, "dispose of invasive plant materials by bagging and placing them in the garbage. Most home compost methods cannot kill the seeds or plant parts that will ultimately continue to spread the plants unless the compost reaches uniformly high temperatures (such as 140°F)." Do not compost deadheaded butterfly bush flower spikes.

What this means practically:

• In Oregon and Washington: per NC State Extension Plant Toolbox, the Lo & Behold series cultivars (Blue Chip, Ice Chip, Blue Chip Jr.) are "approved for sale in Oregon and Washington." Use only these or other certified sterile cultivars.
• In all other states: standard B. davidii can be grown, but prompt deadheading is required. Removing spent flower spikes before seed sets is not optional in ecologically sensitive areas near natural lands.
• In any state: research your local noxious weed list. B. davidii is regulated in some states and not in others. The USDA Plants Database is the authoritative source for your state.