Summarize:

Moss roses are well-known for their combination of beauty and durability. They suit most climates well, and amply reward their caretakers with amazing blooms. However, they do have a few quirks, so double-check to make sure your garden can support them. Moss roses are succulents, storing water in large, fleshy leaves. This means that they will be fine if you forget to water them. They can grow in poor soil or even rock gardens. However, they might drown in a very rainy climate. Moss roses are low-lying, rarely topping six inches in height. They are good for borders and pots, but do not command large-scale attention on their own. Moss roses can absorb the carbon dioxide from car exhaust especially efficiently. This means that they are sometimes used to line driveways, or parking lots. Though some varieties are edible to humans, moss roses are toxic to pets. Do not plant them where a dog or cat can snack on them. Now that you know you're ready for moss roses, it's time to figure out where to put them. Since moss roses love sun, make sure they will get full sunlight for at least part of the day. If you are planning to use them in a flower display, plan to put them in front, as portulaca plants are low-lying. To know how many moss rose plants you need for a border, measure the length in inches and then divide by 12. Your plants should be spaced about 8 to 12 inches (20 to 30cm) apart, so dividing the total measurement in inches by 12 will give you the approximate number of plants that you need to fill the border while still keeping adequate space between the young plants. Don't worry; moss roses grow fast, so you won't have gaps for long. You don't have to plant moss roses outside. They are pretty in pots, too, as long as they get plenty of sunlight. If you are a more confident gardener, you may already be planning to work with seeds. If you would prefer to begin your garden with a little bit of a head start, seedlings may work for you. There are pros and cons to each, so think about it and decide which suits you better. Seeds are cheaper, and you can start growing them (indoors or outdoors) whenever you're ready. However, it can be difficult to wait two weeks for them to germinate, and then an additional month until they're sturdy enough to move. Seedlings are convenient and already healthy, but because a greenhouse has done the work of germination for you, they are often expensive. You can buy moss rose seedlings at any local greenhouse, since they are popular summer plants, though they may be tricky to find in grocery stores. Seeds can also be found in greenhouses or garden supply stores, or well-reviewed online shops.
Find out if moss roses are right for you. Plan out your planting. Decide if you want seeds or seedlings. Get your flowers.