If you would want to take out he jasmine you could build up the bed and plant some annual color. But yes it is hard to grow things under a large tree.
Here is a pic of a bed I did not too long ago at my Fancee's Grandparents.
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I expanded the bed about 3 years ago and did little john bottle brushes around the base with clumps of Stella de aura dwarf day Lillies. It's at the base of a pecan tree but gets a good amount of sun. The bottle brushes didn't make it near the tree so we substituted some lantana this time, we will have good color and little worries.
With the shade you can do something along these lines with plays like impatiens or begonias. Just a thought...
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