Amelanchier not doing well ....

[Plantinyum]

I have two amelanchier plants, planted together, they are small still so no compettition whatsoever. Both of them have yellowing leaves with green vains , most of the leaves are so yellow that they almost get white, at whitch point they dry out and shed. They are planted in a full sun situ, in a clay soil with some pine bark mulch added on top, 3 year in ground and by the looks of the plants, it may be their last, they are just soo weak and unhealthy looking, will add pics later...
How do u people keep those things healthy ? Please share and thanks !! 🥲😀