Trimming thick basal plates

Perham, MN(Zone 3b)

Some mention has been made from time to time about thick basal plates on amaryllis. I would really appreciate it if some of you who know about this issue would describe what the possible effects of such a condition are, and how and when to trim same.

I have an amaryllis that appeared to have quite a thick plate when I repotted it a few weeks ago. It seems to be doing fine, but I'd like to be better prepared for dealing with this next time I re-pot.

And -- I suppose the time to do it would be when bringing the plants out of dormancy? Not, for instance, when I set them into the garden in the spring, when they're still growing.

Thanks for any knowledge and experience you can offer!

Deltona, FL(Zone 9b)

Thick Basal Plates interfere with root growth and will eventually cause the bulb to starve to dead. I generally find them in pots with heavy, poorly drained soil. Amaryllis are susceptible to rot if they are too wet so maybe the thick Baal Plate is an attempt to keep the bulb up out of the damp.

The worst I’ve seen was over 1.50” thick. No roots could grow through it and the bulb was declining in size.

Fortunately trimming a Basal Plate isn’t hard.

Timing: I trim Basal Plates as soon as I find a thick one.

Materials: better soil and/or sand, old, worn toothbrush, isopropyl 70% alcohol (rubbing alcohol), small/narrow paint brush, small, thin sharp knife such as a paring knife, rooting powder.

1. Unpot the bulb.
2. If the soil is wet and/or too heavy, prepare better soil now. Adding 50% sand will improve the drainage.
3. It’s not necessary to trim the leaves.
4. Clean the bulb. Be very careful to protect any healthy roots. Rinse the soil off the bottom of the bulb and the roots. I used an old, worn toothbrush to clean the ridges at the bottom of the bulb. More than 3 ridges is generally a problem.
5. Determine if there are any salvageable roots.
6. Use isopropyl 70% alcohol (rubbing alcohol) to sterilize the bottom part of the bulb and the ridges. I use a ½” wide paint brush to “paint” these areas.
7. Use isopropyl 70% alcohol to sterilize the knife you’ll use to trim the Basal Plate. I dip the knife in the alcohol and then flame it over a sink.
8. If there are no roots, gently peel through the layers of the Basal Plate until only 1 or 2 ridges remain. This is much like peeling an apple. There will be white dots around the cut edge of the Basal Plate where the roots will grow.
9. If there are salvageable roots, cut perpendicular to the bottom of the bulb in-between the roots. I frequently end up with an “X” pattern on the bottom. Then gently insert the knife through the ridges to remove pie-shaped pieces of the Basal Plate where there are no roots.
10. Once all the cutting is done, sterilize all the cuts.
11. Allow the bulb to dry.
12. If there are no remaining roots, wet the cut bottom of the bulb and then dip it into a shallow plate of rooting powder. Repot the bulb to the shoulder sufficiently to keep the bulb stable.
13. If there are remaining roots, gently spray the cut bottom and roots with water. Then sprinkle the roots and cut Basal Plate with rooting powder. I keep rooting powder in a spice container that has numerous small holes in the top. Then repot the bulb.
14. Water and return to a sunny location. Protect from cold below 50°.

I have photos of this somewhere and will try to find some... The only photo I could find quickly shows no leaves, no roots and the thick Basal Plate.

Yes, this bulb survived!


This message was edited Jan 15, 2014 11:57 PM

Thumbnail by Wyckoff
Perham, MN(Zone 3b)

Hi Candace,

Thanks for that detailed report! Just the sort of thing I and I am sure many others are looking for. It ought to be made "sticky", IMO.

None of my bulbs is all *that* thick in the basal plate - just thicker than they were when I got them. I'll refer back to your post when I examine them next winter.



Deltona, FL(Zone 9b)

My professional background is Quality Assurance. I have way too much data on all my bulbs. It's a lot of work but I'm retired and the data is useful.

As an example: I measure all my bulbs. I have a plastic tree caliper which works great. I always measure the same way - straight across between the leaves. I push the caliper down in the soil so I get the fattest part of the bulb.

Visually observing a bulb isn't always enough. A bulb can have 3 or 4 beautiful leaves and look just fine but actually be declining.

The measurement tells the story. Time of year also matters. If I measure in late summer / early fall, then the measurement ought to be greater than the measurement taken at the end of blooming. The bulb had all summer to recover and grow.

If the measurement is the same or smaller, then the bulb is not thriving and I want to know why. Typically I unpot the bulb and the most common issue is a thickening Basal Plate. The earlier the problem is found and corrected, the quicker the bulb starts thriving again.

Basal Plate problems are my own fault since all my bulbs are in pots. I want the soil to have sufficient nutrients but that can make the soil heavy and damp. I should use more sand.

Measurements also tell me a bulb will lose 10 – 20 % of its mass while blooming. I measure as soon as a bud tip appears and again around the 3rd day of "full bloom". If the bulb is too small or has already lost too much mass, I don’t pollinate it.

A bulb can lose another 20% while producing seeds. I generally pollinate only 1 flower to minimize the stress to the bulb. If a second scape has appeared, I sometimes have a dilemma. If a good pollen source is also blooming, I may pollinate and then remove the second scape. Or I may wait to see what other pollen might be available and if the bulb still has enough size to handle seed production.

In my first year of serious breeding I pollinated anything and everything. A couple of bulbs died but they had lost over 50% of their mass. Most bulbs just took 2 or 3 years to recover before blooming again. It was a hard lesson to learn.

Today’s bloomer is H striatum.


Thumbnail by Wyckoff Thumbnail by Wyckoff
Perham, MN(Zone 3b)

Ooooo, I do so much appreciate the scientific gardener! Thanks again, Candace.

My bulbs seem not to want to take a real rest for quite a while after blooming and growing out their big fat leaves. The leaves stay green and appear to be contributing to building the bulbs, even though for a few weeks in early summer they don't put out new leaves. When I move them into the garden this summer I might find a way to check the plates in more detail, if the soil falls away easily. (This is unlikely, come to think of it; they always pretty much fill the pots with roots.) But as I'm reluctant to damage them when they're putting on bulk, trimming will most likely have to wait until after their fall/early winter dormancy, when I bring them in for their annual new soil re-potting. Unless, of course, one is obviously losing vitality; in which case I will probably sacrifice it in the interest of self-education.


Perham, MN(Zone 3b)

I thought I'd update this thread, with illustrations, since I can't seem to find pictures of this process anywhere. The photos seem to have uploaded *not* in the order I meant them to go. So: the 2nd photo is the first one I trimmed. And the result is in the first photo.

Photos 3 and 4 show two other bulbs that I trimmed. I read somewhere that it would be best not to plant them immediately, but to dust the cut surface with Captan (but I used cinnamon instead), and then allow them to dry, before planting.

For other tyros like me, I'll just observe that actually cutting these wasn't any harder than cutting a potato. I thought maybe they'd be really tough and woody, but they're not. Still, a really sharp knife is a good thing to use.

Question: how long should I expect to let them dry? 24 hours? A week?

And more questions: Do you think all these bulbs did actually need to be trimmed? Their first growing season in my care was 2011. So this would have been their fourth year, for all of them. How often do you find it necessary to trim the plates? And to what thickness? I didn't quite dare cut all the way to the bottom of the round part of the bulb, because in most cases there were some roots growing there, that I didn't want to cut off. Should I have just bit the bullet and done it?

When I dug up the bulbs in September, and trimmed the leaves off, would that have been a better time to trim the plates, and then let them sit in the cool and dry, and cure?

All of these bulbs failed to put on the bulk I would normally expect, during the past growing season. They'll probably still bloom, but I bet not as big as what they used to. I planted them into the garden last summer instead of keeping them in pots, as I usually do, in the hope that completely consistent water, rich soil, and plenty of room for expansion would bring them on; but it didn't seem to do the trick. I'm hoping that with this trimming, this will be a recovery year.

I hope the photos and your observations will help others who want to make their amaryllises last years and years. Thanks!

Thumbnail by joanlc Thumbnail by joanlc Thumbnail by joanlc Thumbnail by joanlc
East Texas, United States(Zone 8a)

I plant my hippies inground. Will they develop the thick basal plates? I have notice some have declined but didn't bother to investigate why. In z9a, when would be best time to trim basal plates, if I have them? very interesting, I had never heard of this or at least not paid close attention

Perham, MN(Zone 3b)

Just to be clear: my bulbs declined *before* I planted them out for the summer. Planting them out was an effort to help them bulk up; but it didn't appear to work, in spite of what I think were pretty good conditions. I conclude there are other problems.

These same bulbs, when grown in a pot over the summer after their first season in my care, produced so many roots they were climbing out of their pots. I'm hoping to restore them to similar vigor. (But I've saved and potted up some babies off the sides, just in case.)

Dallas, TX

This is all very interesting. Never heard of the basal plate problem. I do have a question, however. I was given a nice size bulb a year ago Oct. It didn't bloom but I didn't expect it to. I have it in a pot (I think maybe too deep) and it grew 2 long strappy leaves. Don't remember how, but one of the leaves came off, probably when I was 'rearranging'. So - - - should I leave the remaining leaf or cut it off?

I do plan to take the bulb out of its pot to see what, if any, kind of roots it has. And now I'll know to look at the basal plate as well.

Advice about the leaf appreciated.

East Texas, United States(Zone 8a)

Let the other leaf be

East Texas, United States(Zone 8a)

Encourage u to repot bulb so that crown is above soul line, this prevents against rotting and fungus happening at this susceptible location. Stated otherwise plant so bulb is 1/3 above soil line

East Texas, United States(Zone 8a)

Quote from vossner :
Encourage u to repot bulb so that crown is above so line, this prevents against rotting and fungus happening at this susceptible location. Stated otherwise plant so bulb is 1/3 above soil line

Perham, MN(Zone 3b)

Hey TX Flower Child, I'm *nothing* like the experienced grower that Candace and Vossner are, but two leaves is really not much. That's a sad plant. Do take Vossner's advice about planting the bulb higher. Re-evaluate all growing conditions - light, temperature, soil, fertilizer, drainage/water retention etc - and think about what you know about what amarillyses like. I think I usually have 6-8 big fat leaves on a bulb that's happy and going to put on a show in the next year. Good luck!

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