Prunus mume and an introduction to fruit types

Prunus mume (Plum Flower, Japanese Apricot)

Prunus mume (mume pronounced like moo-may), is a tree originally native to Japan and China reaching an adult height of 15-30’. Commonly called the Japanese Apricot or Plum Flower, it is a member of the genus Prunus, which contains several species of fruit trees including peaches, cherries, plums, apricots, and even almonds.

I find the inclusion of almonds in this group is often a source of confusion for the less botanically-inclined. Why would a nut be lumped in with all these fruit trees? In fact all of these trees produce fruits which are considered “drupes”, a fruit type where a single seed is surrounded by usually a fleshy layer fruit. The peach is often a textbook example: think of it as comprising of three parts: the fuzzy “skin” of the peach (exocarp) covering the fleshy fruit (mesocarp) which in turn encases the pit or seed of the peach (the rough uneven outermost layer of the pit is the endocarp).

Almonds are drupes as well, however in this case it is the seed we find edible rather than the mesocarp . The mesocarp and green leathery exocarp of the almond fruit have already removed by the time they reach the store, leaving only the endocarp and embryo. The shelled almonds have their endocarp removed, whereas the unshelled still have the endocarp remaining.

Diagram of a Peach Fruit (drupe) pulled from Wikipedia's entry

 

An example of a “true nut”, botanically speaking, would be something like an acorn or hazelnut, which is produced on the plant with a hardened wall around the seed and no fleshy fruit layer. I’m now thinking of doing an introduction to the major fruit types in a later entry, but for now let’s use peaches and plums as our reference points for drupes.

Despite that we now know the plant produces a drupe, Prunus mume, is not generally known as a fruit tree. Most of the plums you’ve eaten are probably members of Prunus x domestica, a name referring to hybrids of two mainly European species. Prunus mume is instead an ornamental grown for its flowers.

 

I remember seeing a few of these trees last summer upon moving to Delaware, and have been keeping an eye on them since hoping to catch a specimen in bloom. I first became interested in the species when doing a write-up for the Greenway’s Chrysanthemum festival back in Fall 2010. I was trying to find a brief tidbit from Chinese Folklore about the significance of the mum flower to liven up the article a bit and came across a mention of the “Four Men of Honor.” I’m not sure of all the details, but apparently these are a group of plants traditionally believed to possess admirable human traits. The Chrysanthemum symbolizes modesty, Bamboo represents integrity, the Orchid stands for leisure, and finally, the Plum Blossom is seen as displaying braveness.

The brave Plum Blossom! This is actually from the cultivar 'Pendula', though you'd never be able to tell without seeing the habit. Note that there are clearly five petals per flower, indicative of plants in the rose family.

 

We already had bamboo and obviously chrysanthemums in the Chinatown Park, so I thought it would be fun to add the remaining two men of honor. Orchids are a huge family of plants so there were several options there, but I was pushing for Bletilla striata, the Chinese Ground Orchid, which in retrospect may have been a bit too fragile for use in an urban park unless protected in a raised bed or container.  The plum flower on the other hand was much harder to track down. It’s thought of being only marginally hardy to New England as it apparently has difficulty surviving the colder winters. Though I think it would have been at least worth a shot given a protected location, many of the New England Nurseries simply do not have the plant. I assumed that this was due to the aforementioned hardiness issues, but its rarity appears to be nationwide. It is however, decidedly more popular in Japan, with hundreds of named cultivars.

 

I’m not sure if I see the evident braveness in this flower, but there’s definitely something ballsy about coming into full bloom in January. I’m the kind of person who likes being able to walk through a garden at any point of the year and see something in bloom. The offerings for December, January, and the first few weeks of February are understandably quite sparse. Now granted we’ve had what I understand to be a very mild winter in Delaware, at least so far, but when in late January I see a flowering tree that approximates the flowering cherries so representative of spring, I can’t help but feel that season is rapidly approaching, even if I know there are still quite a few cold weeks ahead of us. I’m surprised, but also a bit disappointed this plant is only rarely cultivated here in the US, and will certainly be keeping an eye on it in the future, watching for any particular forms which may be worthy of further evaluation.

We also have Prunus mume 'Hokkai' at the UDBG, which seems to be a semi-double form with darker flowers

Further Reading:
Edible Plums and Apricots