Expert: Long Island Gardener - 10/27/2007

Question
QUESTION: Hello,

I am wondering if you can help me with this amaryllis question?

I have grown in the last 5 years two amaryllis and have had the same results
with both of them.  Each came from different sources.  Both bulbs bloomed as
expected the first year.  Each year after the bulbs continued to slowly shrink
in size and today they are only about 1/5 the size they once where.  I plant
them in the summer in the garden and bring them in before it gets cold.  Then I
leave them to dry later on in the fall and don't water them until about wen they
show new growth which is about late January.  But each year they don't bloom and
through their growing season both bulbs continue to shrink, even when they are
actively growing during the summer months.  

Its like the incredibly shrinking bulb! it will come to a point when they cease
to exist!

This issue has occurred with every bulb I ever had so it really is not isolated
to these two particular bulbs.

My question to you is what is happening to these two Amaryllis bulbs, can it be
reversed and how?

ANSWER: Amaryllis is perennial in Zones 9 through 12.  You did not mention your location, but I assume you're North of Florida ('...it gets cold...') and you can't grow these outdoors.

You indicate your Amaryllis must be dug up while still growing full throttle.  At this point, I'm sorry to say I'm a little confused.  You 'leave them to dry later on in the Fall'.  What happens between the time they come out of the ground and 'later on in the Fall'?  Are they in pots?  Are they in a shed out of the ground, roots and all, sans soil?  What kind of care (if any) do they get -- Sun, Soil, Water, Food, etc?

It's possible this care is the cause of your disappointing deja vus.  Please tell me more.

Meantime, let me add that Amarylllis bulbs WILL shrink if they 'catch' a bug while in the ground during the Summer that causes it (and there are many of those).  I would like to know if you notice any damage when you lift these out of the ground in later Summer/early Fall.  rsvp

---------- FOLLOW-UP ----------

QUESTION: I live in zone 5, and I only but the amaryllis outside during the summer months in the same pots they where growing in during the winter.  I always keep the bulbs  in a part sunlight area and fertilize once a month.  The bulbs are in regular potting soil all of the time during their growing time, and wile they are resting, and are in the same pot all the time.  Once summer ends and it starts to cool of I take them inside (I don't dig them up because their in pots to begin with), usually the bulbs leaves start to turn yellow and fall of at the end of September.  Once they do that I place them in the seller (in the same pots) until they begin to grow around the middle to the end of December.

Now here is the interesting part.  During the bulbs growing season they are actively growing leaves and at the same time the bulbs are shrinking.  During the bulbs growing season when they are growing leaves, the bulbs outer shells or whatever they are start to brown and dry eventually this leaves a smaller green bulb inside the dried outer shells.  During the bulbs dormant period the bulbs don't shrink, only during the growing season.  Another point to make is that these bulbs only bloomed once and that was the first time I had them from when I bout them, from then on they continued to get smaller over a period of about 4 years.  Also the bulbs are never soft or appear to be rotting, in fact they are quite firm and green and appear to be very healthy.    But as I said before the outer part of the bulb turns brown and dries up leaving brown dried skins with a continually  smaller green bulb inside of the dried skins.  

At the end of the growing season the bulb that is left is healthy and green but a lot smaller, and next year they will get a lot smaller and eventually I think they will just disappear!

Also I should note that the leaves are always green and healthy and never show any spots, yellow lines etc..

Now as I said before this has happened with every Amaryllis bulb I have had, and in fact I never saw one actually increase in size for me.  Again my question to you is, can you help me determine what I am doing wrong and why the bulbs continue to shrink and never increase in size instead of getting smaller?  And what should I do different with the a new one if I should buy one?  

If I do purchase another Amaryllis bulb I fear that the same thing will happen to the new bulb, again yet still, if I don't solve the problem I have.

I would appreciate it if you could help me with this problem.      

Thank You very much.

William

Answer
Armed with your new information, I posed your problem to the elite clique that calls itself The Pacific Bulb Society and asked them to opine on what they thought might be going on.  Following are some of their responses.

One gardener, writing from Missouri's Pace Gardens: 'One thing that could be a possibility is that there is an insect infestation of the basal plate.  I have had a larvae of some sort of bug that eats through the basal plate and causes the 'shrinking effect' effect you have described, the healthy looking leaves and all.  If the bulbs are taken out of the pots in the fall and the basal plate inspected you may see a tiny hole in the basal plate.  If the bulb is split you can find the larvae inside the bulb eating away. I have not seen the adult of this larvae, but it will kill a bulb in a few seasons.  I would also suggest putting the
bulbs in as much sun as possible during the summer months...'

What Mr Pace is describing is probably an attack of a Garden Monster known and feared as the Narcissus Bulb Fly.  This sneaky little bug looks NOTHING like a Fly.  How does it look?  Have a look at this photo:

http://www.biopix.com/Photo.asp?PhotoId=45112&Photo=Narcissus-bulb-fly-(Merodon-equestris)

This illustration was sent by still another Pacific Bulb Society member:

http://www.pacificbulbsociety.org/pbswiki/index.php/NarcissusBulbFly

Dead ringer for the common Honeybee, wouldn't you say?

And so this insect pest became the subject of another opining Amaryllis authority from the Pacific Bulb Society, writing from his Canadian Gardens: 'Narcissus flies, the greater and the lesser. They are pervasive here in Victoria, BC, Canada, perhaps because the large numbers of feral Daffodil bulbs growing in neglected places provide reservoirs from which the flies emerge to attack Garden plants.

'All members of the Amaryllidaceae are subject to their depredations, but some much more so than others... The cultivated Hippeastrum hybrids commonly called Amaryllis are definitely subject to damage from Narcissus flies. If you summer your Amaryllis outside and you are in an area infested with Narcissus flies, you should lightly wrap the Amaryllis in cheesecloth to prevent the flies from reaching the bulbs.

'Narcissus flies lay their eggs on the withering foliage at ground level, the grub crawls down the outside of the bulb, and then tunnels up from within. They are mere flies and can be controlled by nearly any standard insecticide (unlike many weevils), but since they are on the wing from the first warm days in early May until about the end of July, you have to spray (and spray meticulously!) about every two weeks over a three month period. Entirely aside from the potential environmental impact of this much spraying, it's simply too much work afaiac.  I have read that if you backfill the cavities left by withering Narcissus foliage with fine sand, this blocks the grubs' access to the basal plates. However I am skeptical about the efficacy of this method.'

Another person, who operates a small business dubbed Telos Rare Bulbs, volunteered her own theory that your problem may simply be a matter of fertilizing properly:  'All bulbs draw on their food reserves to make new leaves, so this would account for some shrinking of the bulb.  Most commercially offered Hippeastrums also have had their roots removed, so they also have to draw on stored reserves to make new roots.  This is a huge draw off the bulb, so no wonder it gets smaller! Just think of those big leaves, and the roots, plus the flower and flower stem -- where does the energy come from to make them?? From the bulb; therefore the bulb shrinks.  This happens normally, and that is what those food reserves in the bulb are for.  Food reserves are then replaced through photosynthesis of the leaves. They shouldn't get smaller every year, though, and if they do they are not being fertilized enough and possibly are planted in too small a pot.  It takes at least two years for a commercially grown Hippeastrum minus its roots to recover and make another flower bud, which will not show up until the third year.'

Yet another Canadian Bulb authority wonders if your potting soil should take part of the blame here:  'Mine used to do the same, exactly, until I put it in the other mix,compost, gravel, perlite.  I still have many of those reduced bulbs and I think it's been about 2 years since transplant and there is no further shrinkage...'

I have dealt with the Narcissus Bulb Fly in my own yard for years.  It has wiped out Daffodils and Oriental Lilies, but not my Amaryllis.  Not yet, anyway.  The effects on Narcissus and Lilium are somewhat different.  The bulbs simply vanish after one season.

So now you have something to work with, and if the Pacific Bulb Society people don't have the answer, no one will.  I'm inclined to believe everything they say.

Thanks for writing.  Any questions, feel free to followup.