By: Jackie Carroll
Chaste trees (Vitex agnus-castus) get their name from properties of the seed within the edible berries that are said to reduce libido. This property also explains another common name—Monk’s pepper. Chaste tree trimming is an important part of caring for the tree. Once you know when and how to prune chaste trees, you can keep them looking neat and blooming all summer.
There are several reasons to prune a chaste tree. Left to their own devices, they grow 15 to 20 feet (4.5 to 6 m.) tall and 10 to 15 feet (3 to 4.5 m.) wide, but you can control the size through pruning chaste trees. You can also control the shape by chaste tree trimming.
Carefully placed cuts can encourage the shrub to put on new growth. Another type of pruning, called deadheading, is important to keep chaste trees blooming all summer.
The best time to prune a chaste tree is in late winter. Even if you’ve never pruned a tree or shrub before, you can prune a chaste tree. These trees are very forgiving and quickly grow back to cover mistakes. In fact, you can cut off the entire tree at ground level and it will regrow at an astonishing pace.
In spring and summer, clip off the spent flowers before they have a chance to go to seed. This allows the plant to put its resources into making flowers rather than nurturing seeds. If you remove the flower spikes throughout the first half of the season, the tree may continue blooming into early fall.
In winter, remove weak, twiggy growth from the center of the plant to keep it looking tidy. This is also the time to prune to encourage branching. Make cuts all the way back to a side branch whenever possible. If you must shorten rather than remove a branch, cut just above a twig or bud. New growth will take off in the direction of the bud.
Pruning chaste trees to remove the lower limbs that droop and hang close to the ground is optional, but if you remove these branches it will make lawn and garden maintenance much easier, and you’ll be able to grow ornamentals under the tree.
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The incredibly tough chaste tree (Vitex agnus-castus) works well for rock gardens and other low-maintenance gardens, because it endures severe growing conditions and requires little care once established. In addition to being heat and drought tolerant, it is also fairly cold hardy, thriving in U.S. Department of Agriculture plant hardiness zones 6 through 9. Featuring fragrant purple flowers that attract butterflies, this rapid growing shrub can reach 15 to 25 feet tall and wide, requiring annual pruning to maintain a smaller size. Chaste tree naturally grows in a multi-trunk tree form, but severe pruning produces a bush form.
Prepare a solution of 1 part chlorine bleach and 9 parts water. Clean the blades of all pruning tools with this disinfectant solution. Add the leftover solution to a spray bottle so you can disinfect the tools again after cutting through diseased branches.
Cut the entire plant back to the ground if it is severely overgrown, misshapen or appears unhealthy the plant will return with new growth in spring and bloom in summer. Repeat this every year if you prefer a more compact, bushy growth habit, or only once every several years to rejuvenate the chaste tree.
Remove all dead, diseased and broken branches back to the nearest healthy branch union, cutting at least 10 inches outside the diseased area. Disinfect your pruners before making cuts elsewhere on the chaste tree.
Cut all lateral branches from the center of the tree back to the points of origin on the main trunk. Remove branches from the lower one-third to one-half of the plant to accentuate the natural tree form. Leave more of the lateral branches in place if you prefer a large shrub form.
Remove tangled, rubbing and crossing branches from the branch tips, cutting just above an outward-facing bud to encourage outward growth.
Cut back as much as one-third of the total plant height if you need to reduce the size of the chaste tree. Wait until the following year to cut more of the tree height, if desired.
Remove expired blossoms as soon as flowers fade in summer to encourage a second flowering period.
Vitex at Quarry2: Good to Grow Vitex2 0619. Chaste tree (Vitex agnus-castus). Credit: Forrest W. Appleton, courtesy. 6/9/04. COURTESY FORREST W. APPLETON
As a nurseryman, I am occasionally asked: “What’s an attractive small tree that grows quickly and has lovely flowers?”
That’s a short list, but one very fine candidate is the Mediterranean tree Vitex agnus-castus. Now, I’ve applied a very broad definition to the word “tree,” because this lovely specimen is actually a large bush that can be pruned to be more tree-like. In fact, it is better known in the gardening world as a chaste tree (more on that common name in a moment). Most trees are, of course, slow growing, but this multi-branching tree establishes quickly and will get to a good size even in its first year. Mature trees top out in the 10- to 20-foot range, depending on how they’re pruned.
The first thing people notice about it is its lovely purple flowers. Plants form long cones of lilac flowers that resemble those found on buddleja (butterfly bush). When mature plants are in full bloom the show is spectacular. Each cone, roughly 10 to 12 inches long, comprises dozens of ¼-inch open-faced flowers, much beloved by hummers, butterflies and bees. Dark green elliptical leaves provide a verdant backdrop for the summer-blooming show and look good the rest of the year. The leaves also exude a pleasing woodsy fragrance when crushed.
Chaste trees are versatile plants. They are showy enough to feature as a focal point in a sunny spot when not in bloom, they blend in with Mediterranean planting schemes. They are an excellent addition to a pollinator garden, especially given that they grow, mature and bloom fairly quickly. Bees are especially drawn to the flowers. Given how cold-hardy and durable the trees are, you can also use them as a privacy screen or to line a driveway. You can also force a second bloom in late summer by removing the first flush of blooms as soon as they fade.
l. Vitex at Quarry.Good to Grow Vitex 0619. Chaste tree (Vitex agnus-castus). Credit: Forrest W. Appleton, courtesy. 6/9/04. COURTESY FORREST W. APPLETON
In reference to my opening comment, the compact nature of these trees means you can tuck single specimens into a relatively small space. Pruned hard, the trees become a dense, multibranching large shrub. They thus make great patio trees and, given a large enough container, can live happily within it for many years.
As to its name: Vitex is derived from the Latin vieo, meaning to weave or to tie up, a reference to the use of Vitex agnus-castus in basketry. The idea (probably erroneous) that this plant promotes chastity led to the castus part of its species name and its main common name (Chaste tree). As to its other common name — Monk’s pepper — that remains a bit of a mystery.
Earl Nickel is an Oakland nurseryman and freelance writer. Email: [email protected]
Cultivation: Plant in full sun or light shade inland in fertile well-drained soil. Amend soil with compost and provide good drainage. Water weekly to establish. After a month, cut back to twice a month, and after six months to a good soak once a month. Hardy to ?'9 degrees F.
Pruning: Chaste trees benefit from regular pruning. In winter, clean out the entire center of the tree, removing all side branches from the main four or five trunks. Remove twiggy growth that tends to crowd the ends of the branches. Specimens can also be cut to the ground in winter. They will sprout in spring and bloom in summer, although later than specimens only pruned as above.
Pests & diseases: Leaf spot and root rot can be problems. These can be limited with full sun, very well-drained soil and avoiding too much water.
The new July 2009 issue of Southern Living features an incredibly entertaining and informative story written by me about three great trees for summer blooms. In case you're too cheap to buy it, let me discuss my favorite tree of the bunch -- chaste tree (Vitex agnus-castus).
Native to southern Europe and central Asia, chaste tree quickly grows into a multi-trunked tree about 10 to 20 feet tall and wide with a broad, spreading habit. It gets its name from the erroneous medieval belief that a potion made from it could curb the libido. In reality, wearing a house dress with orthopedic shoes and multiple nose piercings is much more effective.
That doesn't mean that chaste tree doesn't have its pharmacological uses. An extract made from Vitex supposedly does a very good job of controlling PMS. Which means any of you guys out there who are routinely beaten every 28 days should definitely plant one in the yard.
Blue for You
But the best thing about chaste tree, in my uber-learned opinion, is the flowers. Chaste tree is one of the very few winter-hardy trees out there that sports true blue flowers (although they can also be pink, purple, or white). The one you're looking at here is 'Abbeville Blue.' which bears large, spectacular panicles of deep-blue flowers in summer. Other selections I like include 'Montrose Purple' (purple blooms), 'Shoal Creek' (blue-violet), and 'Silver Spires.' (white). If you buy an unnamed chaste tree tree from a nursery, buy it in bloom so you can see the color of the flowers and the general shape of the plant. A good mail-order source for named selections is Forest Farm.
The Skinny on Chaste Tree
Here are some different ways to use chaste tree in the landscape:
1. As a single specimen in the lawn
2. In a row along a property line or a driveway
3. Limbed-up in a border with lower plants growing beneath it
Few trees are as easy to grow. Here's the low-down:
Light: Full sun
Water Regular moisture at first -- very drought tolerant once established
Pests: None serious
Pruning: Not the tidiest plant in the world. Needs regular pruning to produce an attractive multi-trunked tree. Prune in winter. Clean out the entire center of the tree, removing all side branches from main 4 to 5 trunks. Also remove messy, twiggy growth that tends to crowd the ends of the branches. As an option, cut entire plant to ground in winter. It will sprout in spring and bloom in summer, although later than chaste trees not pruned so severely. You can also force a second bloom in summer by removing the first flush of blooms as soon as they fade.
Salt & wind tolerance: Good
Cold-hardiness: Winter-hardy through Zone 6 in Zone 5, may be killed to the ground in winter, but will sprout and bloom the following summer.
Bee alert: Bumblebees love this plant above all others and will even spend the night on the flowers. Keep this in mind if bees freak you out.
A productive fruit tree doesn't just happen, you need to commit to a schedule of pruning -- to get a healthy tree that can produce high-quality fruit. A pluot (Prunus salicina X Prunus persica), a hybrid that is 75 percent plum and 25 percent apricot, features the smooth skin of a plum and a rich purple flesh that is slightly grainy like an apricot and sweeter that both fruits. Suitable for U.S. Department of Agriculture plant hardiness zones 5 to 9, pluots are heavy bearers that require dormant-season pruning to avoid breaking under the weight of their own fruit come summer. The dormant season is when trees are not growing, commonly from December to late February.
Wipe the blades of your pruning tools down with household antiseptic cleaner. The cleaner is as effective as commonly recommended bleach or rubbing alcohol in sterilizing the blades against fungal or bacterial plant disease, but is less corrosive to the metal of the tools.
Cut dead, broken or crossing branches off at their base with pruners or loppers depending on their diameter. Pruners cut branches up to 1/2-inch in diameter and loppers will cut branches up to 2 inches.
Remove 20 to 50 percent of the fruiting wood -- wood that developed, but did not fruit the previous season -- at its base. Choose branches that open up the canopy of the tree to light and will allow for more complete coverage when you spray the tree against insects.
Pluck off and destroy any "mummified" fruit -- fruit that decays on the tree -- to avoid brown rot, a fungal disease of stone fruit that overwinters on these fruits.
Patricia Hamilton Reed has written professionally since 1987. Reed was editor of the "Grand Ledge Independent" weekly newspaper and a Capitol Hill reporter for the national newsletter "Corporate & Foundation Grants Alert." She has a Bachelor of Arts in journalism from Michigan State University, is an avid gardener and volunteers at her local botanical garden.
Hi everyone, this is my first post! :) My name is Nicole. I live in Ocala, Fl. which is supposedly Zone 9, but we definitely have chills into the teens most winters, so I am posting as Zone 8b.
This weekend, I went to the Extension Office's one day plant sale and got a $10 chaste tree, Vitex agnus-castus. I have seen them around here where they look filled out and full of blooms, so I know the potential of this small tree. I have also seen pictures of them trained as a central leader with a bushy top and they look lovely that way also.
Right now, the tree looks awful. It is about 5' high, one straight branch and a single offshoot from the bottom with a weak branch, about the size of a BBQ skewer. I know this tree needs pruning, but I am afraid of killing it!
If it would be helpful to post a picture, I can do that, but the description says it all. there is nothing to this tree but a stick with some leaves coming out of the sides. The smell is wonderful though, kind of a sage smell. Is this tree related to Cannabis incidentally? The leaves sure look like it, even the smell is slightly reminiscent of. not that I would know about such things )
So, does anyone have any advice on what I should do? I notice from Googling about this tree is widely planted in Texas, not so much in Central Florida. Similar zones, so maybe I should post in Texas gardening forums also.
In the meantime, does anyone know what I should do to encourage bushiness? I am thinking I will plant it somewhere and wait until December to trim it, leaving it 2 feet above ground. Plenty of mulch and a deep water once a week.