What is the difference between bare root, root balled and pot grown plants?

When you buy plants there are a selection of different ways in which you can have them supplied depending on their size and the time of year. Your main options with their descriptions are these:

Bare root
Summary: Getting plants bare root is a great way to save money but there are risks associated too. Bare root plants are usually smaller than 1m if evergreen and so we don’t supply with plants with a bare root. 
Available: only Autumn/Winter time.
Sizes available in: up to around 1m if evergreen or around 3m if deciduous
Advantages: With bare root plants you can keep the weight down significantly (because there isn’t all that soil) and thus shipping can be much cheaper. They are also lighter to move around and plant. 
Disadvantages: When you take the soil of a plant’s root ball there will always be a certain amount of root damage. This needn’t be a problem if the job is done well, the plants are kept well watered and then planted promtly but otherwise the chances of loosing plants are raised significantly. Make sure that the plants you buy come from a reputable source and are freshly dug to avoid disappointment. 
 
Root ball
Summary: Root balling is much more common with larger plants where the roots need to be kept as safe as possible. Survival rates are often excellent and the plants are cheaper than their potgrown rivals. Watch out for the weight though!
Available: Autumn/Winter to early Spring time.
Sizes available in: any (plants over 2.5-3m will often come dug with a machine called a ‘tree spade’).
Advantages: Root balled plants are less costly than their potgrown rivals and because the roots have plenty of room to spread out in the ground the plants will typically be much bushier too. When dug and transplanted carefully there is not need to worry about survival. This is  great way to get bushy instant hedging around 1.2-3m high (above this height the weight of the plants can be prohibitive).
Disadvantages: The largest disadvantage of root balled plants is the weight as that quickly ads up, whatever the soil they are grown in. On the larger plants it can mean that they don’t grown for a season and instead spend that energy getting established but once established they will grow well.
 
Pot grown
Summary: Pot grown plants have huge advantages like being lighter than rootballs and usually having a 100% survival rate. Risk is much lower but the price is a bit higher. 
Available: all year round
Sizes available in: any (from us, up to 4.5m)
Advantages: Plants that come in pots are always lighter than root balled plants because the soil in the pots is typically a well draining compost. That means you can get much larger plants and still be able to plant by hand. Because the roots are contained the pot size can also be smaller and thus easier to transport and plant. Roots are not disturbed when planting and so survival rates are excellent. And to top it all off, they are available all year round. 
Disadvantages: Some pot grown plants can be less bushy than their root balled rivals which makes getting that instant evergreen hedge a bit further away than ideal sometimes. However, there isn’t aways that difference. If a plant has been in a pot for too long it can become ‘pot bound’ where it will take a season or so to get the roots out into the ground this will delay the establishment and growth of the plant.