Eric’s Pet Plant: Dwarf Hardy Orange, Poncirus trifoliata ‘Flying Dragon’

Okay, this may finally do it. For years I’ve been wanting to plant ‘Flying Dragon’, a contorted dwarf form of hardy orange that’s even more gorgeous than the species, and now here’s Eric giving it the pet treatment, just to remind me.

Lack of space and lack of warmth have combined to restrain me, but if I could get one going in a big pot and leave the pot outdoors year ’round…

First, Announcements from the Garden: several events coming up, the date of one we know about and the other two we’re still working on.

On April 30, Arbor Day 2010 at noon, we will be remembering Bruce Carmichael with a tree planting here at the garden. He was a great friend to the garden, as he was to many people both here at Yale and in other walks of life. He will be sorely missed, but always remembered especially as ‘his’ tree will be gracing our gentle slopes for many years to come.

In May, we will be hosting another beekeeping workshop, led by Vincent Kay. The date won’t be decided until perhaps a week before this event, because we must accommodate Vincent’s schedule as he moves hives to and from local orchards. It is a very busy time of year for him, and we don’t want to add to his stress level by setting a date that won’t work for him.

In June, we will open the Desert Display area of the new greenhouse. This display is being slowly developed by David Garinger, our Indoor Plant Curator, whose plant skills are matched by his artistic sense of display. Again, we are not sure of the date, but please keep checking this column and the Marsh Botanic Garden web site for more information moving forward.

Hardy Orange, Poncirus trifoliata

(Note: The colonel has reappeared, after many columns’ absence, more irascible than ever. If you haven’t read about him before, you might want to check the fourth paragraph of  Eric’s New Years Letter before plunging in. LL)

“Many a man hath more hair than wit,” I said, after the Colonel had commented on my glaucus pate.  He had noticed this fact of my physiognomy because I was leaning over cleaning out the debris from around a particularly prickly denizen of his garden.

“And there are those unlucky ones with neither,” he chortled.  “When you are done picking up the trash (a job, I might add parenthetically, you are supremely well-trained for), could you prune that Devil’s Claw or whatever-it-is down so I don’t catch the trash bag on it every Wednesday.”

I looked at the plant in question, and its position four feet from the limestone walkway from back door to garbage can, wondering if he had more swing in his gait than any prancing model on Runway. To prune back the shrub would be a sad business, as it is a very slow grower and doesn’t need pruning for many years, if at all.

“That Hardy Orange, or some call it the Trifoliate Orange, shouldn’t be pruned, Colonel.” I said. “ We perhaps can position some smaller shrubs in front of it to protect you from it (and it from you, if I may use the verbal parenthesis).”

Trifoliate Orange, or Poncirus trifoliata, is a native of northern China and Korea. It really is hardy, listed for Zone 5 in several sources, but I have found reliable flowering and fruiting to be best in Zone 6 and above. Dirr  mentions that it gets killed to the ground at –20 F.

Poncirus is a member of the Rue or Citrus family, Rutaceae. Members of this family share some common traits: flower structure, glands – often aromatic – on the leaves and in most cases, thorns. Some varieties of Citrus have been bred to have no thorns, but the original species have some nice weaponry at their disposal. The genus name comes from the French word, poncire, for a type of Citron, and Poncirus is closely enough related to Citrus that it is used as rootstock for limes, grapefruit and others to make those plants more cold-hardy.

It is also called  Chinese Bitter Orange, for its astringent fruits. They are pubescent (having fine hair) and bright yellow to orange. They ripen in late fall and can remain on the tree for some time. The pulp is a good substitute for lemon, the rind is useful in marmalade and the peel can be candied.

Our own P. trifoliata is a cultivar, or cultivated variety, called ‘Flying Dragon.’ It has a dwarf quality to it and twisted and contorted limbs.  The straight species grows to 20 feet high with a width about two-thirds of that. They are wicked to prune because of the long green spines, but those same spines add a visual interest (along with the left over fruit) in the late fall and winter garden.

In fact they are quite striking, and make this plant garden worthy on their own. Add to these aspects the late April to early May fragrant flowers and a nice yellow fall color, and you have a three-season plant that any gardener would love to have.

I would include a fourth season, for these plants are superb as a barrier for kids, dogs, goats and anything else on foot. They make a powerfully exclusionary hedge, which “no sane person would attempt to penetrate,” according to Dirr, who calls them “…more effective than a good watch dog.”

Good soil drainage is important in growing Poncirus, as is full sun for good flowering and fruit set.  I might plant something in front and around it to keep the trash from collecting beneath its skirts, as it is painful to extract this.

“As long as I write the check, my mincing mattoid, you will accept my orders…” The Colonel’s color was rising, and his forefinger was getting involved in the conversation. I was about to offer soothing words of acquiescence when the lovely Millicent entered stage left.

“Oh please,” she addressed me, “forgive my husband who has been out of sorts since I have locked the liquor cabinet. Instead of his usual alcoholic libation, I am ready to serve you both some tea. I found a lovely bakery in New Haven that makes scones which aren’t exactly right, but ‘close enough for colonials,’ as the Colonel would say, wouldn’t you, dear? I also have some Bitter Orange Marmalade that I made last October, so, won’t you join us?”?

The Colonel looked like he had been pole-axed with the divulgence of the information about his domestic situation regarding alcohol consumption. I cleared the table on the verandah (for it was a glorious mid-March day, sunny with temperature near 60 F), and averred, “I’m trying to cut down as well.  I sleep so much easier, and I’ve lost a few pounds to boot.” Looking at the Colonel, I motioned towards a chair facing the Sound and offered a smile.

“Thank you for the gracious gardyloo, my recrudescent friend, but ‘tis only aboiement to me.” Both his wife and I sat open-mouthed as he sat down gazing at the sun upon the water.

Disclaimer: The opinions and thoughts expressed within these columns are not those of Yale University, Marsh Botanical Gardens, or Leslie Land. They are personal reflections on life, plants, humankind and the daily miracles that come my way.