New growth should be fairly vibrant. I don't think that you have a problem, unless the new growth starts turning yellow. I'd say to wait a while before you make any assumptions about your plant. If you still think there's something wrong, I'd suggest a bit of epsom salt, though there are plenty of folks here who have much greater knowledge about these matters than I.

I was going to say try epsom salt also. I use it once a month on all my plants during active growth. I mix 1 tbls per gallon of water.
Karyn

Thanks, Bismuth & Karyn. Knew you'd know what to do. Plant is looking healthy, but the Epsom Salt RX is easy enough to try. I have been going over my collection of brugs ... cuttings and plants ... and am so surprised at what I've managed to put together and see growing, considering I'm a beginner (only since Oct.) and I have about 26 varieties, plus some NOIDS and also a B. Sanguinea plant (I hope I don't mess-up)lol. So maybe by the end of the season or at least next year I can join trading with you all. BTW, this is really due to the wonderful advice and lessons learned via this friendly, helpful forum. Thanks Big Time... Gloria

I find if you feed the brugs enough, they don't get yellow leaves. I feed mine a handful of alfafa pellets once every two weeks, when I feed the roses.

Epsom

Mix 1 tbsp of Epsom in a gal of water,
Give 1 plant 1 qt of this mix
Wait about 3 days
If the leaves are greener then you need Epsom
If not you don't

Epsom needs to go into the soil so that can dissolve and form
Mg2 + and - 2so4 so the plant can absorb it correctly Do Not exceed 2 tbsp per month per plant, excess causes the soil to go acidic
Chena