Hoodoo makes use of Holly, most often, as sort of doorway guardian amulet and in incenses for blessing dwellings. It is believed that the use of the very plant is “imported” from European lore, perhaps through Christianity. Therefore it is important that we understand the “original” plant’s lore. Conjurers also say how this plant is reputed to attratct helpful spirits into the household.
Old Northern European legends speak of continuous rivalry , and an annual battle for dominion over the Nature between Oak and Holly. Two sacred trees, that Celtic Druid saw kind of twins like, with Holly being like black Oak. Being equal in power , they would defeat one another periodically, and their dominion would be divided on equal parts throughout the year.
That way Oak would rule nature from Winter Solstice to Summer Solstice, and the darker, evergreen Holly would rule the nature from Summer Solstice to Winter Solstice, when most of the trees are bare, leafless and fruitless. Considering that fact, it is only logical that people use branches and loops as protective botanicals against spirits of Darkness and against misfortune. It was also believed by cunning folk to have power to peace the beasts, and invoke kind and helpful spirits to household. It is also said to be powerful guardian against poisons , thunder and evil spirits 
In Christianity, Holly became an very important plant often symbolizing Lord Christ ( respectfully ). It is very possible that the reverence of the plant in Christianity , was adopted from celebration of Yule and Roman Saturnalia. Be it so or not, the Holly was even included in paintings depicting Saints and their life, one fine example being painting of the anonymous author, known as “Master of the Holy family” , who painted seven leafs ( ! ) of Holly on triptych painting depicting life Virgin Mary, called "Seven joys of Virgn" . Christians see pale white flowers of Holly as symbol of Christ’s birth and innocence, it’s red fruits as symbolic of Blood of Christ, and finally it’s thorny leaves are symbolic of Lord’s thorny Crown.
In occultism, Holly represents masculine principle and it Mars/Fire correspondent plant, which can explain its reputation as powerful exorcism agentIvy is said to be its female counterpart, often assisting it in spiritual fights and empowering It , while often entwining it’s trunk as well. It’s even used in some beauty spells , such as Winter Queen water, of which I wrote here :http://shadowsmagickplace.blogspot.com/2011/07/conjure-beautiful-you.html
Now , briefly on the botanical information. Despite the fact we will commonly call Holly a tree, it’s actual ecological form ( life form ) is an evergreen shrub. In magck we use three species mostly , one of which is not commonly called Holly
- Ilex aquifolium, common ( European ) Holly with thorny edged leafs
- Ilex opaca, which differs botanically from the previous by only one taxonomic marker, leafs edges here do not have spines, and those two species are used interchangeably.
- Ilex parguaruensis known also as Yerba Mate, indigenous to Southern USA, used largely into Santeria and Palo, known also as Palo Espanta Muerte, and despite being another species of same gender, does not share magickal correspondences with common Holly, it’s a separate magickal plant , with its proprietary uses and will not be discussed in this post
Holly leaves are used in herbal medicine as analeptic, analgetic , anti-rheumatic and have few other minor uses.
Here are a few of recipes ( ideas on how to use Holly )
Make a loop out of braches of Holly or on a branch of Holly hung a piece of Angelica root and three De**l shoestrings. Such door guardian, form of Gris Gris, will secure the entrance where hung on door lintel so no evil may cross the protected threshold 
Blessed home condition oil
• Holly leaves
• Cumin seeds
• White rose , or white rose petals
• Frankincense resin
• Benzoin resin
All to base of preferably Olive oil or Almond oil, with a Capsule of Vit.E capsule. If You have, You could use Frankincense and Benzoin essential oils instead of resin. Or , optionally You could a dd Sandalwood and/ or Rosemary essential oils to scent condition oil and bring about peaceful vibration ( as they often ingredients of Peaceful home products ).
Beast calming powder
• Holly leafs
Pulverize, sprinkle in front, or blow at animals and beasts, to subdue them to peaceful and calm state.
NOTES: This article was written and composed by myself, therfore should You desire to use any part of it elswhere, feel free but do add credits Shadow of Shadows magick place or Shadowemail@example.com or a direct link to this post.
CREDITS:  According to Cunningham Scott, stated in his "Encyclopedia of magic(k)al herbs"
 Inspired by Catherine Yronwode's entry ( about Holly ) in her "Hoodoo herb and root magick" book
Images, came from www.wikitionary.org , tribe.tribe.net and finally Ogham symbol for Tinne ( or Holly ) was a common picture edited by myself. Pictures used here are without ill will and for illustrative purposes only
Many light Blessings, Shadow !