There are five species of chilli peppers most commonly grown for human consumption. Each of these species has multiple sub species or cultivars leading to the reality that there are actually hundreds of types of hot peppers.
Jalapeno Peppers [Capsicum annuum longum] are a type of chili pepper . The word jalapeno is a deviation of the Spanish word meaning 'from Jalapa' a city in Mexico, where the pepper was originally cultivated. Jalapenos are an annual that can be grown as a perennial in some zones if protected from frost.
Aji Omnicolor is prized for its culinary value but more so for its aesthetic appeal. It grows on a beautiful plant that produces an array of colorful hot peppers that measure 30,000 - 50,000 on the scoville scale. The peppers are 2 to 3 inches in length and fairly thin. They begin as a very pale white yellow and morph is stages to a yellow green, various shades of yellows and oranges, and eventually to a deep fire engine red at maturity. Produces very abundantly, also has peepers at various stages of ripeness and coloration simultaneously.
Billy Biker Jalapeno peppers are relatively large, measuring 2 inches at the shoulder and 3.5 inches in length. Turns red when mature. Named for one time television personality and biker Billy Hufnagle. Scoville Scale average 10,000 up to 30,000 claimed in some instances under horticultural coaxing.
Black is beautiful and this jalapeno pepper wears it well. All Jalapeno's at time develop a black 'blush' on the side taht gets the most sun. Black Jalapeno was bred to be black as midnight. It is fairly sweet so far as jalapenos go registering around 2,000 - 2500 on the scoville scale. Produces prolifically.
Chichimeca is Medium hot. Fairly large hybrid jalapeno at about 4 inches long and 1.5 inches round. Good disease resistance is another factor this plant was bred for. Scoville scale 2,500 - 5,000 average. Up to 8,000 under horticultural coaxing.
Medium hot. 3 to 4.5 inches up to 1.5 inches round. Tolerant of temperature fluctuations, drought resistant but will also withstand cold damp weather for short duration's. Peppers begin as standard jalapeno green and morph to a purple black and eventually a deep crimson red when fully mature. Scoville scale 2,500 - 5,000 average. Up to 8,000 under horticultural coaxing.
3 to 4 inch long fruits 1.5 to 2 inch diameter. Moderately hot at 2500 to a max of 5,000 on the scoville scale.
Medium hot 2500 to 8,000 on the scoville scale. Yields up to two weeks earlier than most varieties as its name implies. Germination in about 14-21 days and Maturity at 60 to 65 days. Taste and texture is comparable to standard jalapeno.
Medium hot jalapeno 3,000 to 8,000 on the scoville scale. 3 to 3.5 inches long with a diameter of about 1 inch. Starts green and matures to brilliant red on a plant that is 1.5 to 2 feet tall.
Fuego aka Jalafuego
3.5 to 4 inch crack resistant peppers. Medium hot, Scovile scale 2,500 - 5,000 average. Up to 8,000 under horticultural coaxing. Not to be confused with another variety of non jalapeno also called fuego.
Medium hot 2 to 3 inches long up to 1.5 inch diameter. Starts out green and matures to red. Early Season variety harvest attained in 60-70 days. Very similar to early Jalapeno mentioned above but Jalpa is a tad higher on the scoville scale sometimes peaking at 10,000 scoville units.
Jalaro Jalapeno aka Yellow Jalapeno
Jalaro is a very colorful variety sometimes grown for its ornamental value. Begins as a golden yellow, morphs to orange and matures as a deep red. Resistant to many common pepper plant diseases. Developed by the Texas Agriculture Extension Service in the early 1990s this jalapeno reaches 8,000 on the scoville scale sometimes as low as 2500.
Jwala Pepper aka Indian finger hot pepper
Originating in India this pepper reflects the Indian cultural craving for hot spicy food. It registers 20,000 - 30,000 on the scoville scale
Medium hot 1,000 to 5,000 on scoville scale. A very big variety that yields an early harvest. Peppers reach just shy of 5 inches in length by 1.75 inches in diameter. Start as dark green and morph to red when mature. They are commonly used green. Best for stuffing, but good for any other recipes.
Medium hot early maturing variety. 2 to 3 inches long by 1 inch or less diameter. Matures from green to red. Produces high yields of very uniform large peppers, prized commercially. The strong upright growth habit and continuous fruit setting throughout its active growth season. Scoville rating of 4,000 to 6,000
Mucho Nacho . This jalapeno is a fat boy that is also fairly hot at 4,000 to 8,000 on the scoville scale. The peppers average about 4 inches long and considerably thicker than other Jalapenos. Has a robust flavor that is not drowned out by the heat. It starts as green and matures to red although it is commonly used green as it makes for an awesome stuffed pepper. Also suitable for any other recipes Jalapenos are used for.
NuMex Pinata. Very colorful display of red, purple and orange peppers. Similar to pretty in purple peppers. Mild flavor 1,000 - 5,000 on the scoville scale.
Orange Jalapeno. Although it is a true Jalapeno it s very mild, almost sweet with very little capsicum content. 2.5 to 3 inches long by less than an inch in diameter. It has a very low capsicum content and a fruity flavor with citrus undertones. If left on the plant past their peak orange maturity they turn reddish and concentrate more sugars becoming sweeter. Scoville scale 2,000 to 5,000 but up to 8,000 under horticultural coaxing.
Purple Jalapeno. Mildly hot measuring around 5,000 on the scoville scale. Frequently grown as an ornamental although it is also valuable as an edible. 3 to 5 inch length 1 to 1.5 inch diameter. Start out green and gradually ripen to a vibrant purple, intermediate shades are colorful blends of purples and reds. These are considered a sweet chilli pepper and are best used fresh or pickled.
Tabasco Pepper is a popular Moderately hot variety reaching 30 - 50,000 on the scoville scale. They are used fresh and in sauces such as Tabasco sauce. The plant tends to have a bushy growth habit. The peppers are tapered and roughly 1.5 to 2 inches long on average. Immature peppers are generally yellowish green and mature to hot yellows and shades of orange.