Plants, trees, and flowers make great science fair projects. In order to have a winning science fair project it should be chosen with something that sounds fun or interesting to do. Begin by thinking about what type of project on them you would choose.
There are several plant collections for science fair projects. The simplest of these are leaf or flower collections. These can be dried and labeled and quite large in the number of plants that are sampled. To make a collection stand out, you need to do a little more. Add information about each specimen, such as the scientific name, where it grows, history of it, etc. More than just the leaves of each specimen can be collected. For example, you could also make a photo of the tree it came from, take a bark sample, or take a seed sample, like an acorn.
Model and Posters
Several projects with plants could be either made into a model or drawn as a poster. The easiest would be a diagram of plant parts. This could be improved by showing a comparison between different plants and how the parts are similar and different. Another could show the life cycle of a plant, from seedling, to full growth, to what happens to the plant after it is harvested. A tree can be shown from a acorn to being made into paper or lumber.
There are many experiments that can be made with plants. Think about the things that a plant needs to thrive and survive: water, sun, air, soil. Many projects can show how changing these inputs can help or hurt the plant. The first part of the experiment should be a "control" plant. The control plant should receive all the normal inputs needed for survival at typical rates. This means it receives a normal amount of sun, water, etc. The other plants can have the inputs changed. These other plants can then be contrasted against the control to see how they grew with the different inputs.
There are many different ways that the inputs can be varied. One way would be to keep a plant completely in the sun or in the dark. Try growing one with something other than water, or with more or less water than is traditionally needed for the plant. Change the soil type from clay to sand or to none at all.
Be sure and record the growth rate of the plants. This could be done in a chart and with a daily journal. Photos could also be made of the plants progress over the period of the experiment. The differences there are, or are not, are the important parts of the experiment.
There are many types of science fair projects to be made with or about plants. Think about what might interest you about plants. By taking your time and making a great presentation, you will be on your way to a project you can be proud of for what you have made and what you have learned. Those are the secret ingredients to winning projects.