Cleaning Azalea Seed

Cleaning Azalea Seed |

Wondering about when to collect azalea seed pods and how to clean them (i.e., how to get the seed out of them)? These e-mails describe how a few experienced people do it, along with some information about azalea seed … and the zen of azalea breeding.

Subject: Cleaning Seed
From: “Ed Collins”
Date: Sat, 22 Jan 2000 14:55:40 -0500

I would be interested in hearing if any of you has a different method for cleaning azalea and rhodo seed than listed below.

I try rubbing (rolling) the unopened pods between my thumb and forefinger. This results in the pod splitting open (50% of the time). I then twirl the opened pod over a tea strainer that is sitting on a white quart plastic container like the type that “Cool Whip” comes in.

I use a pair of long nose pliers to split the more difficult ones then twirl as above to extract the seed. This results in VERY sore fingers. Evidently many people are experiencing the same thing. I met Frank Pelurie several months ago at the Rhodo. Soc. East Coast Regional meeting in Williamsburg VA and he had both thumb and forefinger wrapped in band-aids from cleaning seed. If any of you has a quick easy way for cleaning seed, I hope you will share it with us.

I have quite a bit of native azalea seed that missed getting in the ARS Seed Exchange and will post a list shortly.

Ed Collins………Snowing with 3″ on the ground.(unusual)
Hendersonville, North Carolina   Zone 7   2200ft

Subject: Re: Cleaning Seed
From: “Ian E. M. Donovan”
Date: Wed, 26 Jan 2000 19:53:04 -0500

You generated some great ideas with your question about seed cleaning. I use as a work surface an 8″ x 8″ x 1″ deep dish with a half inch horizontal band around the top edge. It is really an old white, flat, translucent cover from an overhead recessed light fixture. I usually place the seed capsules to be cleaned in one corner and open one capsule at a time using my thumbnail. Once every few years I’ll have collected some capsules too early. They may require a pliers to crush or crack them open. To collect the cleaned seed in another corner of the work surface I use an old aluminum plant label. The chaff is separated into a third corner and dumped when it gets too much. Works fine for me. I can put it on my lap as I watch TV, set it aside whenever I need to and pick it up later.

My objective is to get the seed clean as possible with the least effort.

Ian Donovan
Pembroke, MA
USDA Hardiness Zone 6


Subject: Re: Cleaning Seed
From: Sandra McDonald
Date: Sat, 22 Jan 2000 15:42:50 -0500

I haven’t tried to mash the seed pods with my fingers for years. My fingers are already in bad shape with cuts, splits, and the other woes of people who work with plants, especially in the winter.

I use regular needle nose pliers to semi-crush all the seed capsules of one cross at a time. Then I have a few old wire tea strainers (mostly the larger size, about 4 to 5 inches in diameter). I mostly just use one of the strainers with a fairly large mesh. I have a smaller diameter one with rather small mesh and another size or two I can resort to in the kitchen if necessary. I put a batch of the crushed capsules into the tea strainer and shake it gently up and down over a sheet of clean white paper such as photocopy paper. I keep shaking until it looks like no more seeds are coming out. Then I get another clean sheet of paper and resift the seed onto that, pouring from the first white sheet of paper (slightly creased) into the same tea strainer. That is usually adequate, but you can do it again if you are really picky. With tiny evergreen azalea seeds I use a rather small strainer because the seeds are smaller than the deciduous azalea seeds. Sometimes I might need to blow very gently to get rid of certain kinds of chaff like aborted seed. Sometimes I pick out a few of the larger pieces of capsule. I use the strainers in different ways, usually to strain the seed out of the chaff, but once in a while to strain the chaff away from the seed. Whatever works!

Be sure to wipe off the needle nose pliers well after crushing each separate batch of seed so you don’t get your seed contaminated with other lots of seed.

Sandra McDonald

Subject: Re: Cleaning Seed
From: “E. & J. Deckert”
Date: Wed, 26 Jan 2000 20:10:48 -0500

Here in Maryland, I pick the seeds when pods are mature (mid to end of October) put them into a glass jar, (loosely, not packed tightly together), I then put a cheesecloth over top of jar, fastened with a rubberband, set it on top of refrigerator, or on a window sill, occasionally shaking the jar,and wait until the pods decide to open themselves, at which time, the seeds are ejected. You will then be able to collect the clean seed on the bottom of the jar…No pliers, or other tools needed…This method only works when the seeds have been permitted to mature on the plant………

Subject: Re: Cleaning Seed
From: Barbara Bullock
Date: Fri, 28 Jan 2000 07:54:47 -0700

Very interesting comments on cleaning seed. I just cleaned deciduous azalea seed for the first time, this year. I simply placed the capsules on a hard surface, and rolled a pencil, or a closed penknife over the dried capsules, til they were crushed. The seeds seperated easily. And they’re germinating quite nicely.
Barbara Bullock, Washington D.C.
U.S. National Arboretum, zone 7

Subject: Re: Cleaning Seed
From: “Jean Minch”
Date: Fri, 21 Jan 2000 21:40:06 -0800

After picking the seed pods before they even start or barely start to crack open I leave them dry for awhile and then with my “old timer” pocket knife I slit open the seed into segments and once again leave them spread on a piece of paper to dry. Each of these segments will then open as they dry and release the seeds and then I proceed with a series of strainers, etc. Sometimes a piece of old newspaper is dampened and allowed to dry which raises the fibers. Seeds are spread on the newspaper and allowed to roll gently off onto another paper. This catches a lot of the chaff and fine dust that usually causes mold (black death) when seeds are sprouting. We always store the seeds in sealed containers as soon as possible after harvesting in an old refrigerator between 33 to 34 degrees. The newer refrigerators dehydrate the seeds and cuts down on the mortality rate.

Subject: Re: Cleaning Seed
From: “Jean Minch”
Date: Sat, 22 Jan 2000 03:39:24 -0800

“Seed cleaning” Correction to the method of seed cleaning that we entered – I should have signed Fred’s name to the method – when I saw it on the screen it looked like I did the cleaning and it is ALL done by Fred I am his “secretary” and computer operator.
Jean Minch

Subject: [AZ] Re: Seed pod collection timing?
From: sjperk5
Date: Fri, 09 Jul 2004 12:21:48 +0000

We let the pods start to turn brown.

We then place the pods in brown envelopes to dry at room temperature.
We do not use any drying agent.

After a month of drying we place the pods in cool place.

We clean the seed and then plant the seed or place the seed in a cool

Note: Some plants such as Marie Hoffman can produce seed where none
of the seed geminates.

John Perkins

Subject: Re: [AZ] Seed Pod Chambers
From: Don Hyatt
Date: Tue, 20 Jul 2004 11:16:57 -0400

Having run our chapter seed exchange for quite a few years, I have
shucked lots of seed This year alone I filled 600 packages of more than
120 different seed offerings. To keep from going insane during December
and January, I have spent many hours contemplating rhododendron and
azalea seed so I’ll be happy to share a few thoughts. 😉

All of the native azaleas I have worked with including vaseyi and
canadense seem to have five chambers even though the lattter two have
more than five stamens. Some of the large leaf rhododendrons do have
more than 5 chambers, though. The number of seeds in a pod can vary
depending upon the species and fertility of the cross but I guess you
could expect around 50 to 100 or more seeds in a native azalea seed
pod. The canescens and cumberlandense pods I have worked with usually
have fewer seeds than the other natives, and those pods seem
exceptionally tough. I have often had to use pliers to break them
apart and then sift the debris through screens to separate the chaff
from the seed. I don’t know if this is typical for the species or just
due to the sources we have had in our seed exchange.

The seed size and shape does vary considerably. Calendulaceum usually
has relativel large pods as you point out. Sometimes the pods are an
inch or more long and shaped like bananas but other pods are more oval
and squatty. The seeds are also relatively large (sometimes an 1/8 inch
or more) and flat with wing-like structures on them which I presume
helps the seed to disperse in the wind. Arborescens seed on the other
hand is hard and roundish with no wings… very distinctive among our
natives. It is relatively small (less than 1/16 inch across) and often
dark brown and reminds me of petunia or snapdragon seeds. I have
speculated that its shape might help the seed lodge along the edge of
streams since arborescens does like to grow near water. I wonder if it

Interestingly, some of the plants from Gregory Bald have urn shaped seed
pods with small seeds that are much longer than wide and remind me of
tiny little toothpicks less than 1/8 inch in length. They don’t look
like the typical seeds I have worked with of any of the likely parents
of that hybrid swarm (arborescens, cumberlandense, viscosum, or
calendulaceum) which has puzzled me. Maybe they get the seed length
from one species and then lose the wing structures because of
arborescens inheritance and that creates that new seed shape. Pure
speculation. The deciduous azalea with the largest seed pods I have
seen is a European hybrid called ‘Golden Flare’. It has huge banana
shaped pods often 2 inches in length. Who knows where that came from?
I tried to cross ‘Georgia Giant’, an evergreen azalea, onto that plant
but it didn’t take.

Evergreen azalea seed is much smaller than most deciduous azalea seed
(1/32 of an inch or less) and is usually roundish to oblong with no
wings. It is usually very easy to get out of the pods and quite
plentiful. I really haven’t counted but I guess there might be 100 to
200 seeds in a good evergreen azalea seed pod… plenty to engulf the
entire yard if all of them were to grow.


Mike Creel wrote:
>Don, can I assume that most of the native azaleas
>showing 5 stamens and one pistil will have five
>chambers in the seed pod? What is the typical number
>of seeds that an a native azalea seed pod will contain
>and does seed size vary much. Evergreen azalea seeds
>seem ever smaller than deciduous azalea seeds.
>Species like calendulaceum form much larger pods than
>say canescens.
>Mike Creel, SC, Zone 8a

Subject: Re: [AZ] AZ seed collection
From: Joe Schild
Date: Wed, 21 Jul 2004 00:17:50 -0400

Hi John et al,
Normally, I would reply to John’s questions off list, but I felt my answers may help others in this case so my reply on list.
I will answer your questions out of the order you asked them.
Q. Or can you collect them long before they would open?
A. Collecting seed pods too early can be wrong timing, for the seed will not have had time to mature the germ and there will be low viability. Usually, I collect the pods when they start turning light brown and may still have some green showing, but before they start to split open.

Q. It would help me a lot to find out when you normally harvest your seed.
A. At my latitude, which is very close to yours, I harvest seed from mid
October through early December, depending upon species, cultivar, or hybrid.
In the high mountains of Tennessee or North Carolina, its around the 18th of October, at the same time for good leaf color. In your case, I do not think September will be too late, though some hybrids like the Exbury, Knap Hill and the Asian species do split open earlier than our natives.

Q. Is it necessary to enclose them in some way so that they won’t shatter
before you harvest them?
A. In my garden or nursery, I am looking at plants on an almost daily basis and can monitor the stage of the seed pods. If I was going to be away for an extended period and not able to check the pods, I would suggest purloining a pair of ‘wife’s’ older pantyhose, clip out a section with the foot part and slip that over the seed pods and a section of stem, and then secure it to the limb. The fabric is dense enough to not allow the seed to escape, but porous enough to allow air circulation. Don’t worry about crushing the leaves for there will be new ones next year. (Better yet, go buy several pairs of the nylon footies at K-Mart or the Dollar store. It might make the wife more happy and less likely to do a rant with an iron skillet on the old cranium.)

Keep in mind that some of the early flowering species have seed pods that
would make a bank vault maker proud. An 8′ x 8′ R. austrinum in my garden
has seed pods like made of steel, until a hard freeze, and then they split
open like crazy. The Pinxterbloom and Piedmont Azaleas are about the same. I have been known to slip a paper bag over the clutches of pods, tied off, and then wait for the deep freeze. When it’s time to harvest, I simply clip off the stem into the bag and shake, rattle and sift. Of course, heavy rains may wet a paper bag too much, but our usual fall is dry here.

R. arborescens takes more cold temps to split the pods. I have seen fully
developed pods intact as late as January 30th in the NCCG. R. calendualceum will split pods with the first hard frost as will R. flammeum, R. cumberlandense, R. viscosum and R. vaseyi. The cultivars ‘Oxidal’, ‘Gibraltar’, ‘Primrose’ and “Brazil will split the pods open with a cold breeze, so be prepared to catch them early.

If all the above seems like too much, then consider this; I spend six to
nine months deciding upon a cross; I collect pollen up to three years in
advance, some times; I make only closed pollinations with protected pollen
and stigmas; I eagerly wait for pods to form for several months; I dry and
clean the seed; I sow the seed after preparing many numbers of trays; and
then I transplant to larger containers, grow them off in a heated greenhouse for four months; and last but not least, I wait up to five years to see the first blooms on some hybrids. There is too much at risk to not take care with my investment of time and money. In the end, it helps to be a little crazy to be an azalea breeder. Perhaps, a better way of putting it is, once one is hooked, there is no cure, no magic elixir, no way to stop, and no inclination to stop. My dear wife tells friends that I (me) will be happy to die over my potting bench.

Have fun and enjoy the ride. I can think of a lot of other things worse.
Joe Schild, Hixson, TN USDA Zone 7a