Anything is possible.
The major factor in the size of a plant is how far and can get water and food to the various parts of the plants. Water is more important because food can be produced by leaves almost anywhere in the plant. Massive trees like Redwoods get the extra water they need by absorbing it through their leaves, instead of bringing it all the way up from the roots. This makes massive non-vascular plants near impossible.
Plants have a certain lifespan. Something like a daisy doesn't grow as big as a dinner plate because it dies. Its DNA declares that it dies after it has produced its seeds. A Redwood, on the other hand, can live many, many years, so they can grow very big. The plant needs to be able to live a long lifespan, without getting eaten, to grow big. While it is possible that plant could grow very fast, it would need very good conditions (practically infinte amounts of food and water), and the need to do it. Generally larger plant doesn't die as easily, and can more easily produce seeds, the ultimate goal of most plants.
A plant needs to have the proper structure for its size. A large plant needs to be vascular, with roots, stems and leaves. This allows it to transport large amounts water and food to the necessary places. The plant also needs to have the correct size of stem and branches. A Redwood has a massize trunk (stem). Redwoods don't stand up on the stems of daisies.
To better illustrate my points, I'll explain how the example could be done. A daisy, with its exact genetic could and build, could not grow to the size of a dinner plate. While technically it could transport the water and food needed, it would not live long enough to grow that big, nor would it be able to support its size.
Flowers as big as dinner plates do exist, but they generally sit on the ground. For a daisy-like plant to have that big a flower, it would need a massive, probably wood like, stem. It would likely take a long time to grow. Which breaks the lifespan rule. For it to make sense for a daisy to grow this long, the plant would have to be perennial, meaning it would die over the winter. This plant would be closer to a tree than a daisy. After it reached a certain size, it might produce large, daisy-like flowers. It would probably produce 1 flower per year, and release hundreds of seeds every year. But you probably wouldn't call the plant a daisy.