Don’t Touch Me - Why Some Plants Are Prickly
Why are some plants prickly ?
thorns !
Plants evolved thorns, hairs, nettles, stinging hairs, sharp leaves, spines, and prickles for one main reason – DEFENSE ! To keep browsing animals from eating them or the parts they are protecting.However, not all these structures are limited to defense from physical attacks. In some cases, spines developed to shade or insulate the plants that grow them. They accomplish this by protecting them from the sun or extreme temperatures.
fine hair like thorns shade the plant from the intense sun
For example, saguaro cactus spines shade the apical meristem from the intense summer sun. Opuntia cactus spines insulate the apical meristem in winter from freezing by keeping any snow or ice off the tip. Many alpine plants also developed intense spiny covers to help insulate. But as far as the defensive ones go - here are some you may find in a garden.
Ilex
It is the classic holly of Christmas wreathes, with leathery, evergreen leaves having sharp points along their margins, and dramatically contrasting bright red berries produced in late fall.
Ilex opaca is a native of Eastern US
Opuntia
Eastern prickly pear cactus (Opuntia humifusa) is a cold-hardy cactus native to the Eastern United States. It's hardy to zone 4 (-30 F), which means almost anyone can grow prickly pear fruits at home (even outside the desert).
pretty flowers !
Poncirus
The trifoliate orange, Citrus trifoliata ( also known as Poncirus trifoliata), is a member of the citrus family. A slow growing tree it will only reach 10' at maturity. Early spring will bring a profusion of fragrant white blossoms. Notorious for having long pointy, extremely hard and vicious thorns covering the entire plant.
beware of those thorns !
In China it is grown as an ornamental where its twisted branches and curved 1" thorns are said to resemble a dragon's claws. The seeds of P. trifoliata are used in Traditional Chinese Medicine (TCM) as a remedy for allergic inflammation.Here in the U.S., this citrus is widely used as a rootstock for commercial citrus plantings. It can also be used as a very menacing living fence. Small, green and juicy, very sour fruit will ripen in the late summer. These fruits can be used just like a key lime.
Rose
Scientists explain that roses have thorns as a natural defense. Thorns protect the leaves and flowers from being eaten by animals that are attracted to their enticing fragrance and taste.
Thorns often curve downward to prevent animals from climbing up
Good news ! New thorn less varieties have been developed.
Our favorite thorn less climber - Rosa Zephirine Drouhin
Raspberry and Blackberry
can you tell they are related to roses !
They produce delicious fruit - Beware - they can be an incredibly invasive weed when planted in ground !There are three main types of brambles that grow in the wild. Red Raspberry (Rubus idaeus), Black raspberry (Rubus occidentalis), and blackberry (Rubus allegheniensis).Fruits of each are well sought after by berry picking enthusiasts. Each type has its own unique taste, growth habit, and, for many, secret location. All are covered in thorns !
Solanum
Solanum pyracanthos is an introduce weed which escaped from ornamental culture. The plant is a copious producer of seeds.
pretty lavender flowers with nasty orange spines !
Known as porcupine tomato its stems and leaves are covered in bright orange thorns. It is an evergreen shrub native to tropical Madagascar.
Urtica
A a genus of flowering plants in a plant where many species have stinging hairs. The generic name Urtica derives from the Latin for 'sting'. Called "nettles" or "stinging nettles."Hard to believe it is actually edible when cooked - some say delicious ! That is - if you can pick it without getting stung !!!!!
Urtica dioica
Originally native to Europe, much of temperate Asia and western North Africa, it is now found worldwide. A noxious weed indeed !
OMG this will give you one nasty itch
The hollow stinging hairs called trichomes on the leaves and stems act like hypodermic needles. They inject histamine and other chemicals that produce a stinging sensation upon contact - causing a form of contact dermatitis.
Yucca
Yucca is a genus of tough and attractive plant that makes a great addition to almost any landscape. It produces clusters of white flowers held above green or variegated strap-shaped leaves. They have strong firm leaves that end in a darkened sharp point.
Yucca filamentosa
Known as Spanish bayonet, Spanish Dagger, mound lily yucca, and Adam's needle – all are Florida natives.
Concerned ?
Our Garden Care Team can keep you away from these thorny rascals
or help you check your garden for any !
Call us - let's talk !
PLANT SPECIALISTSGREENING NEW YORK FOR OVER 53 YEARS !
Article written by our Staff Horticulturist, Peter B Morris, BSc, MSc, MBAAll photographs used with permission @SHUTTERSTOCK