What Is Periwinkle?The plant reportedly first came from the West Indies. However, periwinkle was first discovered in Madagascar. Depending on the climate in which it grows, periwinkle is a perennial herb with flowers that can bloom throughout the year. Periwinkle is grown for its unique colors. These colors range from white to green-yellow and lavender. Periwinkle can also be referred to its scientific terms: Lochnera rosea, Vinca rosea, and Ammocallis rosea. A related plant, Vinca minor (common periwinkle, Myrtle) can be used for ground cover purposes.
What Are Its Uses?There are several uses for periwinkle. It seems like they vary widely and that there’s no shortage of them. Let’s take a look…
Traditional/Ethnobotanical UsesThe plant first came to Europe in the mid-1700s. It was first grown as a decorative piece. 250 years later it now grows on practically every corner of the world. Plantations are on practically in every continent, especially in warmer climates. Periwinkle has notably been used in tropical folk medicine, specifically for ocular inflammation and diabetes. Other uses include treatment for hemorrhages, insect stings, and even cancers. Drugs.com note that the specific cancers include leukemia, Hodgkin disease, malignant lymphomas, neuroblastoma, Wilms tumor, Kaposi sarcoma, and mycosis fungoides. Perwinkle alkaloids help improve cerebral blood flow and treat high blood pressure. An extensive body of literature exists on the clinical uses of the various purified alkaloids of Catharanthus.
What Is the Recommended Dosage?Drugs.com notes there hasn’t been any evidence to support a specific dose for periwinkle:
There is no recent clinical evidence to support specific doses of periwinkle herb. The pure alkaloids vincristine and vinblastine are used in cancer therapy at single weekly IV doses of 0.05 to 0.15 mg/kg and 0.1 to 0.2 mg/kg respectively.
How Safe Is Periwinkle?There have been no contraindications yet identified. With regards to safety and efficacy in pregnancy and lactation, information is also lacking. Therefore, women who are pregnant and nursing should not use periwinkle.
Gardening Know HowHere are some more periwinkle tips from Gardening Know How.
How to Grow Periwinkle PlantsPeriwinkle, a broadleaf evergreen plant, is very easy to grow. The plant is drought resistant and needs little other care if properly sited in the landscape. After planting, caring for periwinkle may include the removal of tall weeds in the vicinity. Growing periwinkle in the future will probably block the growth of weeds going forward. A real positive of having this plant around indeed! For the best results, grow periwinkle in a partially shaded area in acidic soil. But as Gardening Know How points out, the plant “can thrive in a variety of sunlight and soil conditions. Growing periwinkle in partial shade creates more vigorous growth. In many instances, extreme vigor may not be desirable unless the periwinkle plant needs to cover a large area. One small plant can spread to 8 feet across.”
How to Grow Periwinkle Plants (Continued)As previously mentioned, growing periwinkle as a ground cover is very common. This is because it seldom ever reaches higher than 4 inches. Periwinkle’s best use is for controlling erosion, as Gardening Know How notes. It is very important to not plant near other species of plant in your garden. This is because it may overtake and choke out valuable plants. Another use for periwinkle is for a climber on non-living support. It is also very helpful for obstructing views when it is used like this. It is vital that before you plant periwinkle to ensure that this is what you want in that specific area. The reason for that is because once you plant it, it is very hard to remove. Periwinkle is not very high on the exotic invasive list. It can, however, escape its original cultivation in your garden. That said, it is seldom ever found going into the wild. One last thought in this section: you should not confuse periwinkle ground cover with annual periwinkle. Annual periwinkle, otherwise known as Catharanthus roseus, is a different plant from periwinkle.
The San Francisco Chronicle
Tips on planting your periwinkles from The San Francisco Chronicle:
First of all, plant periwinkle in a bed with full or partial shade and moderately fertile, well-draining soil. Avoid planting in full sun since periwinkle plants develop yellow leaves if grown under hot, bright conditions.
Since the conditions are most ideal at that time, prepare the bed in spring. Weed thoroughly and remove any stones or other debris. Break up the soil to a depth of 6 inches using a rotary tiller. Work a 1-inch-thick layer of mildly acidic compost into the bed to improve the soil’s moisture retention and nutrient content.
Plant the periwinkle plants on a cloudy, cool day. Dig planting holes with the same depth and diameter as the original nursery containers. Space the holes 4 to 5 feet apart for a traditional ground cover planting, or 6 to 8 inches apart for faster coverage.
Remove the periwinkle plants from their containers. Gently squeeze the root ball to loosen the soil. Nestle the root ball into the prepared hole and firm the soil. Make sure the base of the plant is level with the surrounding soil.
In conclusion, spread a 1- to 2-inch-thick layer of mulch between the plants to deter weeds, and help keep the soil moist and cool. Leave a 1-inch space between the mulch and the base of the periwinkle plants to allow any excess moisture in the soil to evaporate.
Water the periwinkle plants to a depth of 2 inches immediately after planting them. Run the water onto the soil at ground level rather than watering from overhead since moisture on the foliage creates ideal conditions for a fungal infection called vinca stem blight (Phomopsis livella).
The Garden HelperHere is some more insight about periwinkles from The Garden Helper, starting with the types of periwinkle species.
Vinca MajorVinca major, that is, the Big or Greater Periwinkle is prevalent in the United States Department of Agriculture, or USDA zones 7-10. Big Periwinkles are about to grow to about 1-1½ ft. tall. It spreads by long trailing stems that root along the ground as their growth progresses. These types of periwinkles produce purplish-blue two-inch flowers from spring through fall. The Garden Helper notes that “The foliage of V. major ‘Variegata’ features creamy white blotches and margins. One major ‘Maculata’ has leaves with yellowish centers.”
Vinca MinorThe other primary species is called Vinca minor. Other names for it are Dwarf Periwinkle or Myrtle. They are especially found in USDA zones 4-9. Vinca minor is a nearly perfect miniature copy of V.major, as The Garden Helper notes. The publication also points out that “Myrtle is a spreading sub-shrub that grows 4-6 inches tall and can form a dense mat up to 10 ft. wide.” They continue:
They produce lavender-blue, ¾”-1″ flowers from mid-spring until early summer. One minor ‘Alba’ has 1¼” white flowers and lightly variegated foliage. Both Vinca major and Vinca minor are adapt well to growing in hanging baskets or other planters.
Growing Requirements for Periwinkle Vinca PlantsBig Periwinkles can be grown in full sunlight. You should compliment this with copious amounts of water, especially if your primary concern is having a lot of flowers. It is better, however, as a ground cover in partial shade. Dwarf Periwinkle should only be grown in partial or full shade with sunshine in the morning hours. Perennial Vincas grow very well in under almost any soil conditions. This is as long as you drain it properly. For the ideal results, you should mix compost or any other organic material into your soil when you go to plant them. Periwinkles are somewhat drought resistant once you establish them. That said, they grow and bloom best with routine watering. Vincas should be fed every two months while they are actively growing, using a good all-purpose fertilizer applied according to label directions. Shear Periwinkle plants back hard in the spring to promote fresh, new growth and to control spread.
SagaFinally, here is some information on how to grow periwinkle plants from Saga.
Where to PlantPeriwinkles, according to Saga, are “bombproof plants that tolerate shade or light-shade in a variety of soils including acid and alkaline.” They also make good plants for containers. This is especially true for the Vinca minor species. Vincas will always travel towards better light, though. Periwinkles are good when you plant them under trees.
When They FlowerPeriwinkles usually bloom in March. This is due to the emergence of the Spring Equinox.
When to Cut BackIn winter the foliage can become shabby. Consequently, both Vinca major and Vinca minor become hardy enough to be sheared. This encourages both species for fresh spring growth in the spring months. However, it is vital that you don’t shear off Do not shear off Vinca difformis. This is because it is a little too tender as its origin is in the Western Mediterranean. It is prudent to keep a watchful eye for undesirable runners. Pull any that are in the wrong place up from the ground.
Grow With…Vincas are paired very well with spring bulbs, particularly tulips. As Saga points out, the lesser periwinkles (V. minor) go well with robust forms of miniature and shorter narcissi such as ‘Jetfire’, ‘Tête à Tête’, ‘W.P.Milner’ and ‘Jumblie’. The publication continues:
You can use vincas with hardy wintergreen ferns (especially dryopteris, polystichum and polypodium) and with pulmonarias and oriental hellebores for winter interest and spring colour. They can also be grown with robust colchicums like ‘The Giant’ as the evergreen leaves cover up the dying foliage. In autumn, the flowers pop up through the leaves.
Are Rhododendrons and Azaleas Similar Plants and Require Similar Care?
Rhododendrons and azaleas are indeed similar plants, belonging to the same genus. Both require rhododendron plant care tips for azalea lovers. These include providing acidic soil, regular watering, and partial shade. However, it is important to note that azaleas have specific cultivars, while rhododendrons have a wider range of varieties. Nonetheless, both plants share a love for vibrant and colorful blooms, making them popular choices for garden enthusiasts.
Periwinkle VarietiesAs Saga notes, the Lesser Periwinkle, Vinca minor, “offers the greatest choice of colours and flower type.” Periwinkles have various heights. The taller types come under the list of Vinca major (reaching about 18in/45 cm). Shorter periwinkles (reaching about 4in/10cm) come under the V. minor column. Another earlier-flowering species called V. difformis needs more shelter in order to grow successfully. Saga points out the main differences between the shorter and longer forms of periwinkles:
The shorter forms send out far more runners and effectively cover whole areas in a netting of stems. Taller periwinkles tend to send out a few long runners, about two feet in length, and these dip to the soil and root. Sometimes just where you don’t want them. Plant them in areas where spreading and travelling are desirable and don’t be fooled into thinking that the shorter vincas are less invasive. It’s quite the opposite. Consequently, vincas are invasive and they’ve become a real problem in North America and New Zealand. Margery Fish, the famous cottage gardener from East Lambrook Manor, writing in Ground Cover Plants, lists them under Rampers. However I grow some along my stone walls in sunless positions where little else thrives.
Did You Know…? (In Conclusion)To finish this post off, here are some fun facts you will find most noteworthy from Saga:
The English name periwinkle and the botanical name Vinca are both derived from the Latin vincio (to bind) describing the long and trailing stems that spread over the ground.Periwinkles have tannins which are astringent. They also have indole alkaloids including ‘vincamine,’ used widely in the pharmaceutical industry. There are also saponins, which are detergent-like molecules, as well as flavonoids. Common names for periwinkle include the following:” “parwynke, joy of the ground, ground ivy, cockles, cockle shells, pennywinkle, blue buttons, sorcerer’s violet and blue smock.” Here are couple final facts from Saga:
‘Sorcerer’s Violet’ was used for making charms and love potions. Culpeper, the 17th century herbalist, says that if the leaves were eaten by a couple they would stay in love forever. Consequently, it was used to exorcise evil spirits. The giving of periwinkle meant ‘First love – My heart was whole until I saw you’.h/t: Saga, The San Francisco Chronicle, Gardening Know How, Drugs.com