Professional potting soil will usually result in better growth because a sufficient amount of oxygen remains in the pot ( less structureal decay ), which means the roots will not rot away when potting. It is important to have good drainage at the bottom of the pot. If you are not sure this is the case, you can always cut some more holes in the pot. When the plant is potted, you need to water it thoroughly.
There is no life without water. This is also true for your boxwood. The right amount of water depends on different elements, like the type of pot (clay or synthetic material), the type of potting soil, the weather condition etc. A plant in a clay pot will need more water because water evaporates through the sides.
Boxwood and other evergreen plants need to be watered regularly during the winter because evaporation continues through the green leaves.
Some basic rules:
- Summer: check daily and water if required, possibly through trickle irrigation.
- Autumn/ spring: water two times a week, except during heavy rainfall.
- Winter: water once a week, keep the soil moist, but not too wet.
Tip: a tray underneath the pot is useful because that way you have some water reserve. Remove the tray during the winter.
Trickle irrigation is more efficient and more eco-friendly than a sprinkler system.
Boxwood can, in principle, stay in the same pot for three years when potting soil of a good quality is used. After three years or when the growth diminishes you need to repot the plant. You can put the plant in a bigger pot. You should loosen the root ball to ensure good contact with the new potting soil.
If you want to keep in the same pot, you will need to trim the roots. This can be done by making a few cuts in the root ball with an old handsaw so you can add new potting soil to the newly made cavities.
After repotting you need to water the plants thoroughly and add new fertilizer (Osmocote).