That goes against all sorts of advice you have probably heard, and that is exactly why doing this will give you unexpected shots that few other photographers have. Wide-angles are supposed to distort things too much, they are supposed to make perspective look unnatural, they are supposed to be used at a moderate distance so everything looks "normal."
Well, forget normal. Nature photography has gotten way too staid and complacent. The natural world is threatened by many things, but probably the most dangerous thing is indifference by so many people. We had a referendum here in California in the election last week that would have given state parks a huge boost in support and would have cost car owners $1.50 per month. That's it! Yet it was defeated because a lot of people just didn't care.
I find that nature photography today is so pervasive that it becomes simply decoration. That isn't necessarily a bad thing -- nature shots can be beautiful and well worth putting on the wall or using as wallpaper on your computer. We cannot get out and see everything in nature, so nature photography (yours, mine, every nature photographer's work) is how we really do get to see large areas of nature that would be unknown to us otherwise. The danger is that standard, traditional, conservative nature photography starts to all look the same and begins to blend in with the general background "noise" of images that bombard us every day.
A wide-angle close-up is one way to immediately break through that clutter of compositions with something unique and unexpected. Set your wide-angle lens to its closest focusing point, then move in until the subject is sharp. Try shooting with the lens wide-open (at perhaps f/4) for an unusual limited depth of field effect (it definitely looks very different with a wide-angle) and then with the lens stopped way down (say, f/16). Get down low so that more of the background opens up in interesting ways. Even if your camera does not have a swivel LCD, you can still put the camera on the ground and just try this without even looking through the viewfinder. Take the picture, then check your LCD -- if the shot isn't quite right, try it again.
I think it is important to check your shot in the LCD using this way of shooting just because it is not the usual way of shooting close-ups. Looking at the LCD review of the shot helps you see what the photograph is looking like, not just if you got the shot. Since wide-angles do some unique things with perspective and focus up close, it really helps to look at the image and check things like the look of the background. Sometimes moving the camera barely inches left or right can make a big difference to the success or failure of a shot because of the way the subject interacts with the background. This really can be tricky because often the wide-angle will make details in the background show up so strongly that they fight with the subject. Yet, the wide-angle perspective can also help you change that background relationship to the subject if you are willing to experiment a bit.
If you can't get close enough, you can try something I like to do -- use an achromatic close-up lens, such as the Canon 500D. That highly-corrected lens actually attaches to the filter threads of any lens, wide to telephoto, with the right filter size, regardless of manufacturer. I use it with zooms, telephotos and wide-angles. I will warn you that with really wide-angle lenses, that lens may pick up a little distortion along the edges because of the extreme angle light is going through the lens, but if you stop your wide-angle down, this will be minimized -- then again, it can be seen as a dramatic effect! You may also find you get vignetting at the corners with really wide-angle lenses unless you buy a close-up lens that is actually too big for the wide-angle (use a filter adapter ring to attach the close-up lens to the wide-angle -- that's what I do).
Finally, if you really want to have some fun, try a full-frame fisheye up close (a full-frame fisheye refers to the way the lens fills the full frame of the image area, not to the use of a full-35mm-frame sensor size). Many of these focus as close as 5 inches and the effect is extremely dramatic and eye-catching. Tokina makes a neat little zoom fisheye wide-angle lens that does focus to 5 inches and really gives great results. I find using a full-frame fisheye up close to be exciting and invigorating to all of my photography simply because it can be so striking.