When you say near, how near, and is the redbud shaded by the maple (or on the north side of the maple)? How old exactly is the redbud, or how long have you had it?

Bamboo..thanks for your response, the redbud is only about 15 ft from the trunk of the maple, but it gets full sun from late morning until early evening, it's 2 yrs old..Patrick (son) has a beautiful redbud, full sun..no fertilizer..full of blossoms..now i'm wondering if redbuds won't blossom if they get too much fertilizer..Patrick's tree is full size, mine is a standard twisted redbud...

Which fertilizer have you been using, and how often? And while I'm asking more questions, how tall is the maple tree?

thanks, Bamboo..i've been using hen manure fertilizer,a commercial product that seems to discourage squirrels, once in the spring, and once again later in the summer..the maple tree is way, way taller than my home, very old, and there's another one in my neighbour's garden, that's about the same distance away..thanks so much for your interest..

Well, as you suspected, 15 feet away from a very large tree isn't really far enough, so yes, the Maple will be taking nutrients, but most especially, water away from the redbud, not to mention root room. These last two, water and root room are the more critical factors rather than fertilizer. If your hen manure is anything like ours (called chicken poo pellets here) its fairly low in nutrients, but has a higher nitrogen content than it does anything else. Nitrogen is very good for leaf production, not so good at encouraging flowering, you really need a fertilizer with a balanced NPK, something with a readout of around 7-7-7, and that should only be applied in spring, and then again six weeks later if there's time - never feed later than mid June. I wouldn't normally suggest feeding twice in a year with a chemical fertilizer for larger plants like shrubs and trees in the ground, but given the proximity to a large tree, it might help. Might also be worth mulching with something like composted manure to provide nutrients for the soil, and thus for the tree eventually, but don't let the mulch sit against the trunk or mainstem of the tree.

There is a drawback though - if you fertilize the redbud and add organic mulch, the roots from the maple will head for that area (plants aren't stupid, their roots detect where the water and nutrients are!) so its probably best to apply the feed and the mulch around the maple as well, particularly towards the edge of the dripline.

thanks SO much, Bamboo.. I'm going to follow your advice, and keep my little tree..it's a struggle with a very small lot, and nearby large old trees, but even if i only get leaves, i still love it..

It might produce more flowers as it gets older anyway - enjoy!