Butterfly Bush Update
Posted: Mar-21-2005 at 11:05am
more news on the butterfly bush front. . .
in washington, butterfly bush, buddleia davidii, is listed as a class c noxious weed. washington weed list - class c they must be doing a big push on education about this plant because its picture is on their new weed brochure and on the main weed page on their website.
butterfly bush has been added to oregon's quarantine list, approximately 1 year after being listed as a noxious weed. named hort varieties are under study to see which ones to include in the listing. according to my source at oda, there will very likely be named hort varities added to the list because preliminary study shows they have the same invasive characteristics as the species form. i don't have additional information at this point.
conservationists and 'weed police' suggest deadheading your bb to control seed spread until more is known. please don't assume that if you don't see it seed, it doesn't. seed can be carried a long way from your garden - by wind or hitching a ride on a bird - far out of sight of your eyes. in addition, hybrids won't seed true to parent, which makes it impossible to recognize their seedlings. until more is known, assume all varieties seed and act accordingly.
the nursery industry is developing sterile forms. at the portland yard, garden and patio show, i learned of 3 new varieties from proven winnners. look for the english butterfly series - 'adonis blue,' 'peacock' [pink] and purple emperor.' according to company reps, these are the result of 20 years of research, not just for sterile flowers but also for their compact size. they grow 4-5 feet tall and do not require pruning.
hmmm, i think i need to do a little checking to verfy that the new forms are sterile. i heard it from company reps but i can't verify it in print. i'll report back.
Posted: Mar-21-2005 at 11:27am
That would be great news! There is alot of discussion in the horticulture trade about this problem and I have very mixed feelings about it. I love my butterfly bushes and the lists of plants I've seen for substitions just don't cut it. But I really don't want to be part of an invasive plant problem. And I have to admit that my Nanho blue butterfly bush did reseed a few times and I don't think there are any others around so it probably isn't sterile. I am going to try and be really good about cutting off the faded flowers this year. Please keep me informed.
Posted: Mar-21-2005 at 11:43am
It's amazing isn't it, how complex landscaping can be.
One tiny plant can gain such interest due to some aspects such as seed germination.
I can see where they would not want them in the wild because those are rather speedy growers.
(would mean more summer color on a hike though)
Posted: Mar-21-2005 at 8:02pm
I am amazed. I wonder if this is an issue everywhere or mainly in places where the winters are not hard freezes? The only plant I was aware for the longest time that was a bad bad plant was Purple loosestrife and deadly nightshade. Of course there was more then that but none that I really could id. I only knew about noxious weeds from what I read in OG.
So all butterfly bush is bad? None should be bought and planted right now including all the various colors?
Posted: Mar-22-2005 at 10:27am
so far, only the species plant, buddliea davidii, is listed as a noxious weed [a legal classification] in both or and wa, and quarantined in or. named varities are not included in that listing - yet. the study i mentioned above will determine which named varieties will earn the same classification as the species. when that occurs, you will see the named varieties listed along with the species.
as i wrote above, until more is known, it is best to treat all varieties as potentially invasive; deadhead to prevent seed spread.
butterfly bush isn't just a problem here, bakingbarb. it is also a pest along the eastern seaboard. longwood gardens in pennsylvania published a study on seeding habits of bb a few years back. i posted a synopsis of their study along with other other info on this subject on rs but unfortunately those threads disappeared, along with many others, when they were moved to archives. i'll see if i have any info in word that i can cut and paste here because to type it all now would take me way to long as current typing speed.
Posted: Mar-23-2005 at 7:43pm
Lisa it just suprises me considering how may shows used to suggest planting it.
Posted: Mar-25-2005 at 6:55am
I talked to someone who knows about the PW Color Choice shrubs and they said that those varieties should produce less viable seed but we really have to wait for more studies to confirm things. I also looked at their catalog and it doesn't mention anything about it. If you hear about any studies about it being finished please let us know, I would be very interested.
Posted: Mar-25-2005 at 11:07am
oh, drat, fern. i was really hoping that the reps had told us good news but i had my doubts since it wasn't mentioned in any of the literature and they didn't say anything until someone in the audience asked specifically about the seeding habit. i'll continue to track down information. i'd like to determine what 'should produce less viable seed' means.
i hope we get seeding results from the study soon. i know people love their butterfly bushes and it would be nice to be able to recommend which forms are the best of the bunch.
bakingbarb, yes i've noticed that many shows continue to recommend bb but i understand the logistics they must face. each state or region deals with problem plants that can be grown in other regions without any invasive potential. for instance, japanese barberries is considered an invasive in much of the eastern us but it poses no problem for us in the pnw. indeed, it is often recommended to provide color and structure in the garden. while i would prefer that these shows would stop promoting bb, i understand that it is our responsibility, as consumers and gardeners, to stay informed of plant issues for our own regions.
Posted: Mar-26-2005 at 5:19pmSigh all these darn plants to stay away from! LOL I am kidding, we have talked about what 2 plants to stay away from.
Posted: Mar-28-2005 at 11:27am
!!!Whoa!!! They may be on to something, because last spring I planted a new yellow buddlea globosa and this spring I have already given away 3 seedlings about 24 inches high and have 5 more smaller ones! Any takers?
Posted: Mar-30-2005 at 8:00am
Oh no! Even that one? I thought that one wasn't supposed to be a problem.I think I'll just stay away from them for awhile. Back, vicious butterfly bushes!
Posted: Mar-30-2005 at 4:08pm
sorry for delay in more info but it is taking me longer than i'd suspected to learn more details. even if new forms' seed is less viable, they can still pose problems since the species sets a high quantity of seeds, similar to purple loosestrife. for instance, 20% viable seed of something that can set 100,000 seeds is still a lot of seed to spread around. in addition, it is possible for sterile hybrids to regress and produce seed in plants a few generations down the line [this has occurred with other hybrids]. i've been given some leads for more concrete info; i'll report asap.
until i do, it is best to treat all buddlieas as if they are plotting their escape from your garden and deadhead, deadhead, deadhead. a benefit from this watchdog tactic is a shrub that will produce more flowers for you to enjoy [and deadhead again].
yikes, cj, i thought b. globosa was one of the 'safe' ones, too. good to know although i wish it weren't so.
Posted: Apr-04-2005 at 6:42pm
i received the following in an email last february, with permission to relay it along:
State Weed Board takes action on invasive plant that can harm reforestation efforts
Popular butterfly bush added to noxious weed list February 25, 2004. . . Sunday morning garden shows often promote the butterfly bush as a desirable ornamental plant for homeowners. After all, its flowers are attractive and its nectar alluring to butterflies and hummingbirds. But the plant apparently has an evil flip side. That's why the State Weed Board has added butterfly bush to its noxious weed "B" list.
"It's a popular ornamental plant, but it has extreme invasive qualities," says Tim Butler, supervisor of the Oregon Department of Agriculture's Noxious Weed Program. "Like other noxious weeds, it is very competitive with native plants."
With its showy flowers, fast growth, and ability to grow in poor soil conditions, it hardly seems right that butterfly bush should end up on a list with such nasty-sounding plants as bull thistle and medusahead rye. But it has been a huge problem in New Zealand and the United Kingdom. Now it has negatively impacted the United States. In Washington, escaped butterfly bushes have been known to grow in the cracks of pavement or sidewalks, reaching as high as ten feet tall.
"B" designated weeds can have an economic impact and are regionally abundant, but may have limited distribution in some counties. Eradication is probably not viable, but control efforts are very much a part of the state's strategic plan.
Even though the butterfly bush species itself (Buddleja davidii) has been listed, there are a number of commercial cultivars with most of the same qualities but not considered to be an invasive risk at this time. Officials will concentrate on wild populations of butterfly bush that are harming the natural environment.
"We are not going to ask someone to pull out a prize butterfly bush from their yard," says Butler. "The plant is not on a quarantine list and is not prohibited at this time. However, it still is a big concern to us."
A trip to Coos County last year opened the eyes of state weed control officials. While visiting private timber land, Butler and others observed large populations of butterfly bush outcompeting young Douglas fir seedlings that were planted as part of a reforestation effort. The site was miles away from any residential areas where butterfly bush might be planted, suggesting that the wind can carry seed a long distance.
A letter from the Coos County Commission was sent to the State Weed Board urging that butterfly bush be listed as a noxious weed. Last week, the board complied.
ODA conducted a statewide survey this past fall to see if butterfly bush was a problem elsewhere. Populations were found all around western Oregon, including the Portland area. Again, it appears seeds have unintentionally spread from ornamental plants in someone's yard. There is evidence that intentional dumping of yard debris can lead to the introduction of butterfly bush in remote areas.
"We see it as an escaped plant that has gotten away from landscapes," says Don Richards, a nursery industry representative on the State Weed Board. Richards has consulted with the industry about the problem and says nurseries are in agreement with the listing, even though some actually produce and sell butterfly bush varieties.
"The largest growers of butterfly bush in the northern Willamette Valley are very supportive of a control program that might eliminate a problem," says Richards. "The growers want to make sure there isn't some other ornamental variety that might become a weed problem in Oregon. There are many cultivars of the plant. If some are found to be a problem, growers just won't produce them anymore."
ODA research funds directed to the nursery industry are helping to identify any other varieties of butterfly bush other than Buddleja davidii as a potential invasive species. Cultivars of butterfly bush are common and the plant is easy to hybridize. But in that hybridization, it's not always clear if some of the undesirable characteristics of the original plant are passed on to the new variety.
"We are looking at the relative invasiveness of cultivated species," says James Altland of Oregon State University's North Willamette Research and Extension Center. "There appear to be differences in the number of seeds produced, their germination, and many other factors when cultivars are compared to the species davidii. We will visit nurseries that are producing these cultivars to see if they are escaping the site. We want to know if cultivars can be grown safely without threatening the natural environment."
In the meantime, only the original species of butterfly bush, Buddleja davidii, is subject to the noxious weed listing. That's enough to keep officials busy.
"Butterfly bush is not going to be easy to eradicate," says ODA agronomist Glenn Miller. "It seems to come back after herbicide treatment. It could be a tough customer."
The message to homeowners and gardeners does not include a plea to pull butterfly bush out of the ground. It does include general awareness.
"We want people to select cultivated varieties, not the straight species," says Richards. "Also, they should observe any spread of young seedlings away from the initial plant. If they do see the spread of butterfly bush, they should try to keep it under control."
For more information: http://oda.state.or.us/Plant/weed_control/index.html or contact Tim Butler at (503) 986-4625.
Posted: Apr-04-2005 at 7:16pm
in november 2003, bruce newhouse, npso president, emailed a public request from oda, asking for help mapping butterfly bush populations. in conjunction with that, bruce sent me an article about butterfly bush that appeared in the american nurseryman magazine, dated july 15, 2001. i wrote a summary of the lengthy but very interesting article for posting on rainy side and a few other sites. here is the summary [my comments in italics]:
The article is written by Dr. Tomasz Anisko, curator of plants ate Longwood Gardens and Unchae Im, a plant collector at Chollipo Arboretum in the Republic of Korea.
B. davidii was introduced into Great Britain at the end of the 19th century. By the middle of the 20th, it was already reported as being thoroughly naturalized in wasteland in southern England. Today it is ranked as one of the top 20 invasive weeds in Great Britain. (Wow!) It is also a problem in New Zealand (introduced in the early 20th century) since the first report of an escaped B. davidii in 1946.
"In the US, B. davidii is not yet listed as a noxious weed (see footnote below), although it colonizes roadsides, abandoned railroads, rural dumps, streamsides and similar disturbed habitats from Pennsylvania to North Carolina and west to Kentucky and W. Virginia. It is also reported to naturalize in California, Oregon and Washington."
The article mentions its ability to produce copious amounts of viable seed in its first year, its rapid growth, it extensive root system and its decline as it ages. The rapid growth allows the species to suppress and displace other pioneer plants that occupy the same sites. (These are the concerns I've heard mentioned, because often the pioneer species losing ground to B. davidii are native plants. Bruce Newhouse told me, in an email a year ago, that an area near Highway 58 bridge that crosses over Salmon Creek at Oakridge has been colonized at an alarming rate. "Everywhere there is a butterfly bush, there was a native willow, and those willows were being used by western tiger swallowtails and other native butterfly species as caterpillar host plants . . . the butterflies cannot use "butterfly" bush as a host plant. Their reproductive habitat has been lost from 25% to 75% along those stretches of the creek, and the b-bush is continuing to increase.") Method of seed dispersal is wind.
"Ornamental and landscape qualities of commercially available species and cultivars of Buddleja are being evaluated as part of extensive shrub trials at Longwood. This allows us to test seed production and seed germination among these plants. Prolific seed production may not necessarily imply than an exotic plant will become invasive, but certainly poor seed set and poor viability prevents naturalizing in most cases."
Amount of seed set was studied (by weight of the tiny seed). "The weight of seed produced by a single infructescence ranged from zero grams in B. lindleyana 'Miss Vice' , which translates to no seed per infructescence to 1.25 grams in B. davidii 'Potter's Purple', which translates to a staggering number of about 40,000 seeds per infructescence." (Wow!)
"Taxa that produced sparse seed . . . included B. fallowiana, B. hemsleyana, B. longifolia, B. nivea and B. x weyeriana (a hybrid between B. davidii and B. globosa) . . . and its selections. Prolific seed producers . . . were all B. davidii cultivars such 'African Queen', 'Border Beauty' and 'Potter's Purple'. Out of 35 tested selections of B. davidii, only two - 'Orchid Beauty and 'Summer Rose' - produced less than 0.1 gram of seed per infructescence."
The article includes information regarding seed quantities, qualities (including a few species which produce unwinged seed, which likely will impair dispersal), and germination rates (92% in B. davidii var. nanhoensis 'Alba'). Other B. d. forms with germination rates over 80% included 'Dubonnet', 'Navajo Blue', 'Orchid Beauty', 'Peace', 'Potter's Purple', 'Summer Beauty' and B. d. var nanhoensis 'Mongo'. (I'm unfamiliar with these forms but I'm not sure whether that is because these are forms available on the east coast or because I haven't looked at a B. d. for sometime because of invasive concerns)
"One Buddleja - B. lindleyana 'Miss Vice' - which did not produce any seed - could be declared as not having invasive potential in southeastern Pennsylvania and in other areas in the Northeast with a similar climate. However, because it has a suckering habit (and thus is weedy within the garden) and small inflorescences, this plant offers no alternative to showy - but highly invasive - selections of b. davidii." (Doesn't that sound like some kind of Murphy's Law?)
"Because of their relatively smaller number of seed produced and lower seed viability, hybrids such as B. xweyeriana and its selections, as well as many of the less frequently cultivated species, such as B. fallowiana, B. hemsleyana, B. longifolia, B. macrostachya and B. nivea, pose less threat of becoming invasive than B. davidii and its selections. Interesting, large differences in the amount of viable seed were recorded even among B. davidii selections. For example, cultivars such as 'Summer Rose' and 'Orchid Beauty' produced 20 times fewer viable seeds than 'Potter's Purple' and 'Border Beauty'.
At the time the article was written, Jon Lindstrom, assistance professor of the University of Arkansas, Fayetteville, was attempting to develop sterile hybrids of Buddleja by crossing strains of B. davidii (a tetraploid species) with B. lindleyana or B. nivea (a hexaploid taxa). Since these hybrids are sterile they would be non-invasive. The article stated that it will take several years before plants are thoroughly evaluated. (This is an exciting prospect. It would be a great alternative with the flowering beauty of b.b. without its invasive potential for those who feel they can't be without a butterfly bush. Has anyone heard any further information regarding these attempts?)
To control spread of existing plants in gardens everywhere, "a simple routine of deadheading or pruning in fall rather than in spring should be practiced". (On the east coast there might be more risk of increased cold injury to the plants with fall pruning but that may not be the case here.)
Foot Note: At the time the article was written, July 2001, B. davidii had not been listed as a Noxious Weed. However, in 2003, King County, WA and Yamhill County, Oregon added butterfly bush to their Noxious Weed listing. In 2004, B. davidii was added to Oregon's noxious weed list. In 2005, B. davidii was added to the quarantine list. Sometime in 2004/2005, B. davidii was added to Washington's noxious weed list.
To my knowledge, there hasn't yet been a comparable study on the west coast. While many plants behave differently in our region than on the east coast, the fact that B. davidii has escaped garden boundaries and is increasingly drawing the attention of the ODA, Washington state's weed board and conservation groups, the study's information should not be discounted, IMO.
Butterfly bush continues to be among the top plants recommended for many situations (drought tolerant, butterfly habitat, fragrant flowers, etc) by many (too many!) sources and I think a more complete picture of this plant is warranted. If anyone knows of additional resources on this topic, please let me know. TIA!
Posted: Apr-20-2005 at 10:44am
I'm still waiting to hear news regarding the new English Butterfly series of Buddlia davidii. I have gotten in touch with a rep from Van Essen, who has forwarded my request for info to Spring Meadow for clarification. I'll post as soon as I hear news.
As for that study done here in Oregon regarding seeding habits of Buddlia davidii, I've heard a rumor that it may not have begun yet, which means that results and information is farther off than I'd hoped.
I'll keep everyone posted.
Posted: Apr-30-2005 at 8:17pm
I also haven't noticed any for sale lately at any of the local nurseries I've visited the past couple of weeks. If you have a garden and a library, you have everything you need.
Posted: May-01-2005 at 11:19am
I do see them at grocery stores.