Kalanchoe daigremontiana, also known as Bryophyllum daigremontiana, (other names includes: Mexican Hat, Evil Genius, Devil's Backbone, is an upright succulent perenial that originates in Madagascar and can grow up to 3 feet tall with leaves that can reach up to 8 inches long and up to 2 inches wide. They require minimum care and are tolerant of dry conditions and high temperatures. Of interesting note is that there is a second species called Mother of Millions (Kalanchoe or Bryophyllum Tuberosum) that is often confused with the daigremontiana variety. Bryophyllum daigremontiana grows large blue green leaves that reproduce by seeds and vegetatively by growing tiny plantlets along the marginal edges of each leaf. These plantlets are often seen when the parent plant is approaching the end of it's life cycle. At that time the tiny plantlets will fall to the ground where they will take root giving you many more plants.
The best time to propagate more plants is during the spring and summer. If you choose to propagate more plants keep them isolated in their own container or be prepared for them to over run your garden as the tiny plantlets on the end of the leaves will eventually act as volunteers spiking new plants wherever they touch ground. Tiny plantlets can appear along the margins of every leaf inspiring the name Mother of Thousands. Once you have one of these plants you will eventually have thousands of them if you choose to grow more. They are a perfect plant to give to your friends as gifts because they are both spectacular as well as easy to grow for those who are succulent plant lovers. They will flower very colorful, blooms that will attract the attention of any plant enthusiast. Plant them in a terra cotta pot with good drainage holes. Terra Cotta containers accentuate their beauty.
The blooms are stunning, any where from pink, to magenta or orange, consisting of a chandelier-like inflorescence of long-lasting flowers that have a tubular shape resembling cathedral bells. This is a plant that prefers a sunny location especially during the summer months but will do well even in semi-sun. As a succulent they are drought tolerant needing only moderate watering during the summer. If potted, the soil can be tested to determine if water is needed by sticking your finger 2 inches below the soil surface. If the soil feels dry then water to moisten the soil but do not let the plant sit in standing water as most succulents do not appreciate wet feet which will often rot the roots if this is the case.
During the winter months watering can be reduced and if your plant is potted you can bring it indoors placing it near a sunny window where it can receive direct morning sun. At least 4 hrs of sunshine will provide this succulent all the light that it needs to thrive. Like most succulents, extreme heat can be tolerated but freezing temperatures (below 40 to 45 degrees F) should be avoided. If you live in a colder climate, your plant should be brought indoors before the first frost.
As far as soil type is concerned, cactus potting mix will work best. If not you can use 1 part peat moss blended with 2 parts loam and sand which will work just fine. Overall, just about any ordinary but well draining potting soil will be effective as they are not very particular to quality soil and can often be seen growing in sandy loams.
Fertilization can be done every 3 months between March and September using a mild/weak liquid fertilizer or slow release pellets which will be effective to keep these succulents thriving and looking beautiful whether grown indoors or outside. I use slow release pellets so that I don't have to worry about keeping my plants on a feeding schedule. As your plants gain height you may prune away old flower stems to allow good air flow around your plant which will help to prevent any issues with mildew or bugs. In outdoor landscapes and the wild, the plant cares for itself well enough that it can be left to it's own devices.
Be very aware that all parts of this species of Kalanchoe is considered poisonous/toxic to both animals and humans. There are some species of Kalanchoe/Bryophyllum that are edible and considered medicinal but this is NOT one of them.