Pachysandra is a genus of four or five species of evergreen groundcovers or subshrubs, belonging to the Boxwood Family. This species is native to eastern Asia and southeast North America (Pachysandra procumbens), some reaching a height of 8-18 inches, with only weakly woody stems. The leaves are alternate, leathery, with an entire to coarsely toothed margin, and range from 2-4 inches long.
The Pachysandra procumbens (Allegheny Pachysandra or Allegheny Spurge) is a native flowering plant   to southeast United States from West Virginia and Kentucky south to Florida, and west to Louisiana. The name Allegheny is sometimes spelled Alleghany.
It is an evergreen subshrub, growing to at most 12 inches high, usually less. The leaves are 2-4 inches long, with a coarsely toothed margin. The flowers are small, white, produced several together on a terminal raceme approximately an 1 inch long.
Another common species used is the Japanese Spurge,P.terminalis, which is an aggressive spreading evergreen grouind cover.    All species in this genus prefer a well-drained soil with a high humus content.
Pachysandra requires regular watering, approximately an inch of water per week from rainfall or the 'ye olde watering can'. Soaker hose or drip irrigation are a good choice until it is established.  Once the pachysandra is established it only requires watering during drought and before the ground freezes in late fall.  Once the ground is frozen the pachysandra should be watered deeply once a week.
Have good soil with lots of organic matter added each year and if you mulched your newly planted pachysandra beds, they will need watering only when it has not rained for a week or two. If you have poor soil with little organic content or if you choose not to use mulch, then you may have to water the plants every sunny day, at least until they are well rooted. This is especially true for pachysandra growing in containers.

Fertilize newly planted pachysandra at planting time or in the spring by sprinkling some fertilizer on the soil around each plant if you have not already mixed it into the soil when preparing the planting bed. Avoid getting it on the leaves.  Use a handful of fertilizer for every 4 square feet or so of pachysandra bed. If your soil contains lots of organic matter, a single application of slow-acting fertilizer will give the plants a continuous supply of nutrients through the season. If your garden soil is not terrific then consider spraying the plant foliage with some liquid fertilizer about 3 weeks after you‘ve planted them.

Spread a 2 to 4-inch layer of an attractive organic material like wood chips, chopped leaves, shredded bark or dried grass clippings, alone or combined with peat moss on the soil around newly planted pachysandra plants to control weeds until transplants grow together to form a ground cover carpet. This mulch also reduces soil moisture loss through evaporation, and cools the soil. It gradually decomposes and adds organic matter to the soil by means of weather and earthworm activity. This adds vital nutrients and improves its structure and drainage. After several years, the fall leaves that settle in between the established plants will provide sufficient mulch.

If some hard-to-control perennial weeds such as bindweed or thistle pop up later on, either pick them by hand, or use a broad-leaf weed herbicide product.  To avoid killing the pachysandra, wipe the leaves of the weeds with a cloth soaked in the herbicide product. Take care to keep the cloth from contacting the pachysandra and wear waterproof gloves to protect your bare skin.