I don't know how much you have already found out about yellow buddlejas, so forgive me if I am teaching my grandmother. Firstly, they are shrubs, not herbaceous perennials, so you might get more help over on the shrubs forum. Secondly, there are 2 likly candidates, Buddleja globosa and Buddleja x weyeriana. There are various named cultivars of each. Again, forgive me if you already know this but neither looks quite like B davidii in bloom. Globosa has spheres of yellow /orange flowers and x weyeriana has looser clumps of flowers arranged in lax racemes, but neither has the long inflorescences of davidii. So if you were imagining a standard-looking 'Butterfly Bush' but with yellow flowers that's not quite what you'd get. Both grow to the same sort of size as regular B davidii and respond to the same pruning treatment. Both are reputed to be slightly less hardy than B davidii. As to companion plants I'm not sure whether you mean things that would look good, or things that would have some sort of supposed mutual benefit. The first is a matter of taste and the second, IMO, would be irrelevant to Buddlejas. I suggest you Google the two named yellow species above and see what you think.

I've seen some very well grown Buddleia weyeriana Honeycombs in bloom and I thought they were gorgeous. They looked enough like the "davidii" that I had no idea that they were different forms of the Butterfly Bushes that I grow, so I learned something here today. They were similar in size to my plants too. Apparently they were fairly hardy in our zone because they always came back. They grew at a home next door to a house where my daughter had lived somes years ago.

Bluestone Perennials has a write up on Honeycomb along with a picture and some general and plant care info that might be helpful to you.

Linda

I have Honeycomb, new to me this year. I love it! It does have slightly different bloom shape. There's also one (I think also Honeycomb) planted at a garden center I pass on the way to work. Theirs seems a little smaller than the usual Buddleia - maybe 5 ft?

I wouldn't plant buddleia this late in the year. They're marginally hardy, and best to plant in the spring so they have all summer to establish.

Deanna

Oops, sorry. Just noticed you said next year.

Deanna

The mention of orange turns me off. I might be better off with the davidii. I am planning for next year in my yellow area and I don't like when the different types of yellows fight. Do Buddleia's do OK with sun from 10-2? or do they really need full sun all day.

They do a LOT better with sun all day, or a good 6 hours. Your time limit should be OK though. I do have a couple in a spot which gets sun from 11 to 3 with dappled shade at other times. They flower a bit less so next year I'm going to try cutting them back a bit to bring out more blooms. I realize the blooms may be smaller and later, but that's fine by me. :O)

My Honeycomb doesn't bloom nearly as prolifically as the two others I have (one lavender and one a royal purple). It also doesn't seem to attract butterflies, bees or hummingbirds like the others. I've had it for about 4 years and am thinking of pulling it out and replacing it with another type.

I had a "Honeycomb" variety which I agree did not bloom as prolifically, but still pretty nicely. It was a great plant/shrub but I moved it in the summer and it did not like that. Eventually it died the following year. It was very reliable until I did that. Hummingbird moths loved the plant. I knew I was taking a risk, but I had to move it for other reasons. I've not replaced it, but I do miss it. It probably got to about 6 feet tall. I liked purple flowers with it - but really it worked with anything.