Pencil cactus, also known as the milk bush or Euphorbia tirucalli, is an intriguing and versatile addition to any indoor gardener’s array of plants. 
The pencil cactus is one of the most popular houseplants, distinguished by its long, skinny ‘pencil-like’ stems; hence the name. The plant’s skinny branches are covered with petite leaves that emerge in late spring and early summer, lending it an elegant yet robust appearance.
Although called the pencil cactus, it’s important to note that this plant isn’t a cactus but a succulent. This means it is a drought-tolerant plant, adapting to survive in regions with low humidity. It grows very well in pots, as long as they have drainage holes to prevent excess moisture accumulation and, in turn, root rot.