It is hard to resist the sunny cheerfulness of the dandelion---even when it is peeking up at you from your carefully manicured lawn, so it is no wonder we want to the feeling it evokes indoors where we can enjoy it. Dandelions, unfortunately, have exceedingly long tap-roots and do not make good potted plants, but you can substitute a dandelion look-alike suitable for potting.
Dandelion Color and Form
The closest to a dandelion in both form and color would have to be the PomPom and Cushion Mums (Chrysanthemum species). Both varietal types have full "furry" heads, come in a selection of colors, and range from only a few inches to shrub-sized in height and spread. You can learn more about mums at the Minnesota Agricultural Experiment Station. According to their website, "The University's mum breeding program is one of the oldest public sector breeding programs in the world and the only one in North America." They are responsible for discovering the "cushion" habit of mums.
A Bear of a Dandelion Substitute
If you have the space and a large pot (at least 15 inches deep), you cannot go wrong growing the cheerful Teddy Bear Sunflower (Helianthus annuus). It grows about 2 feet tall and has bright, fuzzy yellow flower heads sure to make you smile. In addition, it is exceptionally easy to grow and maintain.
Close, and Just as Yellow
They are not exactly the fluffy powder-puffs we know as dandelions, but they are close and come in a range of upbeat yellows and oranges. French Marigolds (Tagetes patula) is a well known plant that is easy to grow and maintain in pots---especially window boxes. The Figaro variety of Dahlia, which grows only 12 inches in height, is another pretty plant that ranges from yellow to pink, red and white. Strawflowers (Helichrysum species)---which come in nearly every hue imaginable---round out this group. Try H. bracteatum ("Bright Bikinis"), which grows only 12 inches tall.
Pink and Blue Dandelions?
The asters (Callistephus chinensis) are another good dandelion-like group, but they do not come in yellow. If fuzzy is what you are after, however, the tiny Starlight variety, at only 8 inches is a good bet for a potted plant. It comes in all the usual aster colors from white, through several shades of pink, violet and blue. Carnations are neither yellow nor fuzzy, but they have something of the look of dandelions (if you squint your eyes) and smell great too. Some varieties grow as low as 6 inches.
If all else fails, you can always plant the easy to grow and easy to find Zinnia. Grow the cactus flowered varieties for the best dandelion look, but be warned, they are rather tall at 30 inches or so. Zinnias flower profusely and make great cut flowers as well as potted plants (but you will need large containers). Gerberas are another good choice, and are smaller.