Several species offer quite intense yellow flowers - orientalis and tangutica - but they are more bell-shaped and smaller than the common large flowered hybrids. A true yellow is still a unachieved commodity in these. The yellow LFH's tend to be more of a creamy white color, if that.

Here is a link that might be useful:

I have Bill Mackenzie and it is supposed to be a true, dark yellow but I just planted it last fall and haven't seen it bloom yet.

Carol

Here is a link that might be useful: Bill Mackenzie

Where did you get yours at? I like the Bell Shaped ones.

Mine came from Brushwood but they are sold out. I checked Chalk Hill but they were sold out too.

Carol

I have Helios and Bill MacKenzie and they are definitely yellow.

BorS, have you had your Bill Mackenzie for very long? Do you like the blooms and how big does yours get?

Carol

buyorsell88

Does your Helios have a coconut scent?

I've been eyeing this one for a few months now. Do you recall where you got it?

~Chills

Not BorS, but Helios when it lived in my garden definitely had a coconut scent. I think I got mine from a seller on eBay.

I bought my orinetalis labeled simply 'Orange Peel', which I have come to discover is just a common name applied to any these vines with golden, lantern-shaped flowers with a thick fleshy texture. I think it must be a 'Bill McKenzie' or a seedling thereof, as it has many of Bill's attributes including very intensely colored flowers, gorgeous seedheads that persist through winter and an extremely vigorous habit. This is another huge vine for me, growing to the top of the same apple tree the armandii has overtaken, easily 25-30'.

It also has a very long bloom season in my area, producing its first flowers in midsummer and continuing until late September. It also causes quite a lot of comment from folks walking through the neighborhood who are curious to know what that big tree with the nodding yellows flowers through summer is :-))

nckvilledudes,

Did you purchase seed or a plant? (I've seen the seed on ebay, but not plants recently)

~Chills

You can order the Golden Clematis 'Helios',

(Clematis tangutica)from http://www.directgardening.com/detail.asp?ProductID=7647 or http://www.4seasonsnurseries.com/detail.asp?pid=7647. It's flowers are deep yellow with a coconut scent.

Since this thread is three years old I assume the OP already bought one...