help! lotus declining

ErinMiller(10 CA)July 19, 2013

After almost 3 months of tripling in size w/ new leaves almost every day, my lotus began declining a few weeks ago! Can anyone tell lotus newbie what to do?
Details: bought 3-gal dwarf lotus pot from a reputable nursery, added 3 lotus fertilizer stakes around rim (as specified by manufacturer for that size container) then placed it 4"-5" under water on submerged base in 2' x 2.5' metal barrel pot w/ bubbler filter. Given that pot's location btwn 2 bldgs only has sun approx 10:30/11:00 to about 1/2:00, I purchased lotus cultivar that does well w/ half day of bright shade. Fairly constant marine layer here @ beach (sunset zone 22); temperatures range from generally mid-70s (day) to mid-60s (night), although few days in mid-80s around July 4th. windy sometimes...very happy, beautiful plant w/ stunning growth for about 6-8 weeks.
Then, about 3-4 weeks ago, found some dark aphid-like bugs on leaves & tried to remove them by hand before infestation grew. Two days later, found scale as well on some leaves and many stems. Did hand removal again. Infestation increased. So, since there were abundant leaves without pests, went for nuclear option & cut off all infested leaves + stems @ water line (about 10-15% of leaves).
About 7-10 days later, noticed lotus decline: No new leaves for 14 days & existing leaves die from center out (see photos). Also lost all my duckweed or azolla.
About 5 days ago basically changed all water... 4 small new leaves came up w/in couple days. No big new big more small leaves since.
What can I do? Pls help.
BTW, Water here is very high in phosphates.

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ErinMiller(10 CA)

another image...couldn't get more than one to upload on 1st post

    Bookmark   July 19, 2013 at 9:04PM
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catherinet(5 IN)

A couple things come to mind.......
-Lotus need alot of fertilizer. When I had mine in pots, I fertilized them every 3 weeks.

-3 gallons is awfully small for a lotus.....even a dwarf.

-I've heard that if you cut a lotus stem and it gets water in it, it can kill the plant.

-I don't know if the large metal container is good for it.

-lotus love high temps and lots of sun. Your 3 hours a day sun is not enough, and the daytime temps are pretty low.

    Bookmark   July 20, 2013 at 7:23AM
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ErinMiller(10 CA)

thanks so much for writing me.

couple clarification:
the lotus plant (perhaps 2- 4 tubers but hard to tell because of soil) came in a 3-4 gal "squat pot" from the grower; as directed, I placed that pot inside another pot that is approx 2.5' tall and wide. there is a perforated base under the lotus' pot to keep it at the right height.

My light meter indicates that the location actually gets about 4 hours of light mid-day. When I spoke to the grower, he said that would work for this cultivar, esp since the place is bright shade during most of the day.

My thinking w/ a metal outside pot was that it would absorbs heat during the sunlight hours, & keep the water from being too cool at night...I'll get a thermometer and check the early afternoon tempt to see if it's too high...what would be appropriate temps?

My light meter indicates that it actually gets about a little over 4 right now, but of course that will decrease as summer wanes.

the slow release, aquatic fertilizer stakesI used said they were annual, but I wondered about adding more -- that's always a thought when a plant stops growing. Maybe get some really small aquatic stakes and add a 1/3 or 1/4 dose?? What do you use for fertilizer?

Thanks again.

    Bookmark   July 20, 2013 at 1:00PM
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catherinet(5 IN)

Hi erin,

I used to use Pond tabs, but lots of people here said they used Jobe's tomato spikes, so I started using those.
In your size pot, I would probably use 2 at a time, every 3 weeks.

I would say that is good to keep the water temp about at least at 80F to keep it happy.

I know the guy told you it doesn't need alot of sun, but I really think they do. 4 hours just isn't enough.

I am concerned about you having cut off all those stems, considering what I've heard about what happens when you do that.

I would say the number 1 thing you should do is get it more sun. Then fertilize it. Then talk sweetly to it. :)

    Bookmark   July 20, 2013 at 11:09PM
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