Peppers (scientific name: Capsicum) constitute a genus of 20-30 plants. However, only five species are what we know as truly cultivated peppers. We all pretty much know how peppers taste, right? However, do you know the details about the looks of their vegetative parts, their flowers, and the conditions they’re adapted to? Do you know how to recognize different species of peppers according to their traits? Let’s explore the properties of peppers and learn a thing or two about their botany.

Pepper plant classification

As said priorly, there are five pepper species in cultivation. These are:

• Capsicum annuum
• Capsicum baccatum, 
• Capsicum chinense, 
• Capsicum frutescens
• Capsicum pubescens

You may be confused at this point because you know a lot more types of peppers. That’s because each of these species has an astounding number of cultivars, varieties, or types.

Types of pepper plants

Now, we’ll explore the most famous and interesting varieties of each species.

Capsicum annuum and its cultivars and varieties

Capsicum annuum is probably the most cultivated, influential, diverse, and economically important of all pepper species. First of all, all sweet pepper species, most notably bell peppers, originate from C. annuum species. Secondly, some notable chili pepper species, such as cayenne peppers, are also descendants of the species.

Sweet peppers

Bell pepper varieties are usually categorized according to their colors. Thus, we have:

• Red bell peppers
• Yellow bell peppers
• Orange bell peppers
• Green bell peppers
• Purple bell peppers

Also, there are bell peppers that don’t have the exact bell pepper shape but are pointy and elongated. These are called long sweet peppers. In general, all bell pepper varieties, plus some barely pungent chili varieties, are called “sweet peppers.” Lastly, C. annuum also includes some attractive ornamental cultivars with pungent fruits. These include

• ‘Black Pearl’ – it is called ‘black’ due to its dark purplish foliage color
• ‘Bolivian Rainbow’

Capsicum annuum notable chili varieties include

• Cayenne,
• Jalapeño,
• Serrano,
• Thai chili peppers

However, all of these chilies are considered moderately pungent. The record breakers, according to the level of hotness measured by the Scoville scale, belong to the next species.

Capsicum chinense and its varieties

Capsicum chinense varieties are commonly known as Habanero-type peppers. Some of these varieties hold the records of the hottest peppers in the world. Besides pungency, they are celebrated for their specific aromas. Some of the numerous C. chinense varieties include:

• Habanero
• Fatalii
• Carolina Reaper
• Trinidad Moruga Scorpion
• Bhut Jolokia or Ghost Pepper
• Jamaican Hot
• Datil
• Red Dominica
• Scotch bonnet
• Congo pepper

Interestingly, the “wrong” name of the species originates from 18th-century Netherlands, designating that the species is from China, when in reality, it is from South America, like other species of peppers.

Capsicum baccatum

The shape of Capsicum baccatum varieties is often starkly different from what you see in chilis. Besides the unusual fruit form, they are known for their pungency and attractive, in some cases citrus-like, aromas. The most notable varieties are:

• Bishop’s crown
• Amarillo chili
• Lemon drop

Capsicum frutescencs

Capsicum frutescens is actually a wild-type chili pepper. It has small, upright and pointy fruits that change color from pale yellow to bright red as they mature. There are cultivars with more colors, such as purple. These traits made this pepper species primarily decorative plants. Still, it has at least one significant culinary variety – Tabasco pepper, the main ingredient of the Tabasco sauce.

Capsicum pubescens

Capsicum pubescens, the rarest species of the pepper bunch, is interestingly unknown in the wild. It is found in cultivation only, primarily in Central and South America – the native pepper land. The species’ main distinctions are its hairy foliage and rounded colorful fruits. Their taste is hot, but not so much as with some other pepper species.

Biology and Ecology of Peppers

Botanical characteristics of peppers

Pepper plants are robust, branching annual herbs or subshrubs, with some being perennial in their native climates. Depending on the species and the variety, the average height of the plants is between 0.5-1.5 m. The following are the common botanical characteristics of pepper plants – the phyiscal traits that make them different from other plants.

• Root and stem. Peppers have a robust central taproot and many lateral roots. The stem is relatively thin – up to 1 cm in diameter, but commonly less, especially with wild-type species. It is green to brown-green in color and branches out profusely; in some cases, it is hairy close to branchings and can have purplish spots near stem nodes.
• Leaves. Leaves are simple, alternate, usually with an ovate leaf blade with a narrowing or pointy tip – it varies from type to type. The most common color is light to dark green, with some cultivars such as ‘Black Pearl’ having unusual, dark purple foliage. Leaf petiole can be up to 10 cm long.
• Flowers. Flowers are usually single and terminal (at the far ends of stems), small, star-shaped with white petals and bluish or purplish anthers.
• Fruits and seeds. Fruits are botanically non-pulpy berries. They are elongated and hollow, with numerous whitish-yellow, rounded, flat seeds that measure 3-4.5 mm in diameter, carried inside an ovary in the upper portion of the berry, right below (on the inner side of the fruit stem.

Pepper plant development (life cycle)

The flowers can be pollinated or self-pollinated, producing fruit in the end. All peppers reproduce via seeds contained in their fruits. A pepper plant is a prolific producer, and the seeds get spread through human consumption and trade, as well as through consumption by animals – primarily birds, which are not affected by the hot chemical component capsaicin as they lack the targeted pain receptors. Once they fall to the ground and get slightly buried, peppers require moisture and temperatures above 65 degrees Fahrenheit to germinate. In temps from 70 to 80 degrees F, germination takes about a week, and some varieties germinate better than others that perform poorly in this respect. The young pepper plants grow swiftly, and the typical growing season lasts 60 to 90 days. However, in tropical climates, peppers that are grown as annuals in temperate regions can be perennials. Ironically – C. annuum – whose specific Latin epithet means “yearly” – commonly grows for more than a year in its native area. The longevity winner is probably Capsicum pubescens, with individual plants known to last 15 years in their native range.

Habitat of pepper plants

All peppers are native to tropical America – mostly South America, while C. annuum is thought to originate from Mexico. In these areas, they can thrive even in very dry soils once well-established. Peppers are found in different types of habitats depending on the local ecosystems in their native countries. For example, in Colombia, they grow in forests that can be dry, sub-arid, sub-humid, or humid, up to altitudes of 1500 m; in Peru, they grow in forests, but also on rocky slopes; while in Bolivia, they are found in in the rainforests, mountain lowlands and dry valleys, at varying altitudes 0-4000m As an introduced species, C. annuum can escape from cultivation and establish itself freely in non-native gardens and natural ecosystems – though it is not yet considered invasive. Thus, today, it can be found growing in suitable climates in various parts of the world.

How to identify pepper plants

Because of the number of varieties, it may happen you mix up your pepper cultivars by mislabeling seeds or seedlings – or getting the wrong kind through trade. The most reliable way to identify an unknown pepper variety is to look at and try out its fruit. However, there are ways of identifying pepper plants – or at least narrowing the possibilities down to the level of species – even before it fruits.

Tips for identifying different pepper plants by their characteristics

Here are some common trademarks of different pepper species and varieties.

• Flowers: Purple flowers usually indicate a C. annuum variety; white petals with greenish stains indicate C. baccatum.
• Leaves: The leaves of different pepper varieties can look quite similar, though they have their distinctions when compared to each other. However, it can be said with certainty that dark purple leaves belong to either C. annuum ‘Black pearl’ variety or C. chinense ‘Purple reaper’. Also, C. pubescens are the only pepper species with hairy foliage. 
• Fruits. The fruits that grow upwards, pointing towards the sky, are commonly seen in C. frutescens and C. annuum chilies, but the trait is not seen in other species. C. bacctatum can have an unusual, ‘non-peppery’ shaped fruit, such as in the case of Bishop’s cap.
• Seeds. C. pubescens varieties plants have uniquely black seeds.

If you are enthusiastic enough, you can recognize some pepper species according to their taste, aroma, and pungency.

• Sweet and fresh-tasting peppers belong to C. annuum. The chilis of the same species have a smokey and “dark” aroma.
• C. baccatum peppers are hot but also have a bright and fruity aroma. Likewise, the texture is crunchy due to the thick fruit walls.
• C. chinense peppers have varieties that are the hottest in the world, so be very careful if you believe you’re about to taste a Habanero-type pepper. Besides the exquisite pungency, these peppers have a specific, floral, or fruity smell and aroma.
• C. pubescens peppers are usually medium-hot, with the fruits softer in texture and somewhat fruity. Also, these peppers are quite rare.

As you can see, even recognizing a species is sometimes not easy – let alone a specific cultivar! Keep in mind that there are literally thousands of pepper varieties. Thus, the only way to know the variety for sure is to trace the seed source.

Common diseases and problems with pepper plants

Like other plants, peppers can also catch various plant infections and pests. Sometimes, inadequate care can cause disease-like issues but also make the weakened plants susceptible to true pathogens and pests. What are some of the common pepper plant problems? How do they manifest? Read on to find out.

Common pepper diseases

Mosaic Virus

Symptoms: Yellow, Spotted, Hardened, Wrinkly Foliage The tobacco mosaic virus is a common plant virus transmitted by aphids. It can affect vegetables from the Solanaceae family – tomatoes and peppers included, as well as tobacco. Like other plant viral infections, mosaic virus disease cannot be treated. Remove diseased plants and treat others for aphids. The removed plants shouldn’t be composted and are best destroyed by burning. Do not plant peppers, tomatoes, and related plants in the same spot for at least a year, as the virus is known to survive in the soil for around a year.

Blossom end rot

Blossom end rot affects pepper fruits. It is not a pathogen-caused disease but is most commonly caused by a calcium deficiency in the substrate. Other reasons may include excessive salts in the ground, irregular watering, nitrogen-heavy fertilizers, improper soil pH, and irregular watering. To combat blossom end rot, be mindful of securing enough calcium in the soil and water regularly, at steady intervals.

Common Pepper Pests

Aphids

Aphids live in colonies and suck the sap from plants. Taking away the nutritious sap can cause curled, wrinkly, and/or stunted leaf development. Also, transmit plant viral diseases, and their excrement (pee/poo) promotes the expansion of damaging sooty molds. There are many ways to control aphids – you can squash colonies by hand whenever you see them, increase populations of predatory insects such as ladybugs and lacewings (Neuroptera) that devour them, and use (preferably organic) insecticides that target aphids. Tobacco hornworm. Tobacco hornworms are not “worms” but caterpillars of a Tobacco Hawkmoth (Manduca sexta). The caterpillars are fatty, green, and have a red “horn” structure on their rear ends. The sad fact is that they not only eat the leaves but also the fruit of sweet or bell pepper plants, leaving open, extensive scars. The safest and most direct way to fight tobacco hornworms is to remove them by hand-picking. They are large and easy to notice – and tend to be hiding near defoliated areas, on stems’ undersides.

Spider mites

Spider mites are called that because they produce visible webbing on the infested plants and live inside of them in colonies. Like aphids, they suck on plant parts but do best in hot, dry conditions. The plant’s leaves go pale and become spotted white, with webbing appearing soon after. They can cause leaf drop, stunt plant growth, and kill young plants. To prevent spider mites, mist plants regularly, especially in hotter parts of the growing season. For existing infestations, use biological or chemical control (again, preferably organic) that targets spider mites specifically – they are arachnids, meaning that insecticides don’t work.

Pepper plant care issues.

Underwatering or dehydration

You will notice underwatering by pale, droopy, wrinkly foliage. Also, the soil around the plant will likely be super-dry. There is an increased risk of dehydration in hot weather, as well as in potted plants. However, once the plants are watered (when the afternoon heat goes down!), they may lose some leaves, but otherwise should bounce back.

Overwatering or bad drainage

The main signs of overwatering are yellowing, drooping leaves, leaf loss, and soggy soil. Overwatering symptoms occur with – you’ve guessed it – direct overwatering, rainy periods, but also with bad pot drainage, even if watering is normal. To fix overwatering, be mindful of how much you water your plants, check the drainage holes in pots, and see if the substrate needs to be amended or changed to ensure better water-draining properties. If spotted in time and solved, overwatered plants should be able to recover.

Sun scorching

Symptoms: White, wilted leaves; dry whitish-brown patches on bell pepper fruits. Even though pepper plants require full sun, some varieties are prone to sun damage, especially their fruits. These include bell peppers, whose large fruits are sensitive to the hottest summer rays. In sunburned plants, you’ll see white, wilted foliage and dry, pale-brown burns on the fruits. Young plants can also be sensitive to sun damage if they are exposed to the full sun too hastily. To avoid sun scorching your pepper plants, plant sensitive varieties in part-shade or provide garden sun shades. Harden off the young plants before planting them out in the full sun. If you would like to learn more about how to care for pepper plant then check out this guide.

Conclusion

Most of us know a thing or two about certain pepper fruit shapes and tastes. However, far fewer people know something about pepper plant biology as a whole. We hope you now know these diverse plants a bit better thanks to this article – but by all means, keep on learning and feel free to ask questions (comment section included)!