Leaf drop?

[Cherie]

hey guys, I'm new here

I got some hibiscus from the local store (home depo), they've been doing great outdoors all summer (i live in Minnesota). I had to bring them inside last week, i've put them by a southeastern window and have 4k lumie lights on them and have reduced their watering only because the soil is taking a bit longer to dry out.  I also use a 3 in 1 flower spray for mites etc.  
What I'm worried about is i've seen a TON of leaf drop, they went from very full bushy dark green plants to sparse looking- yet they are still blooming. The blooms aren't as big or bright as they were, but there are a ton of buds.  I figured there would be some drop from the shock of being brought inside, but I didnt think they'd drop this many leaves. And i dont see any spiderish looking webs, so i'm not totally convinced its mites. I use the 3 in 1 spray every few days.

 I do have pics if anyone would like to see them.
Any advise would be appreciated! I am hoping I dont fail these plants so I can order some really awesome ones next spring!

[Charlie]

Hi Cherie,

Moving hibiscus indoors should not cause leaf drop by itself. I'm wondering why you chose last week to move them in. If it was in reaction to a much colder night or two the cold snap could well be the cause of the leaf drop. As you mentioned, spider mites are a common cause and could be the problem here, too. Change of humidity to drier and a change in light could have triggered it but the change would have had to be drastic. The main way hibiscus have of adjusting to conditions is to drop leaves or grow new ones so it can be a puzzle to figure out just what they are adjusting to.

If you can post some photos that might help to figure it out.

Charlie

[Cherie]

Thank you for the reply!
The forecast said it was going to start getting below 50s at night so I decided to bring them in. The tree shaped bush didn't actually start dropping leaves until it had been in the house for the week, the smaller bushes were pretty much right away.  I thought it was mites at first with the smaller bushes (the tree is a apart from them), and started using the 3 in 1 spray but it hasn't slowed down at all.  The one plant has very little leaves left, i don't see any webs, and I don't know why the spray would'nt be working?  I'm thinking about trying the bath tactic tonight and see what happens, i'm getting worried they'll have no leaves left in a few days. Though I have *no* idea how i can lay the tree down in the bathtub it's way to tall.


Here are a few picks, excuses the boxes lol bit messy around here atm

[Charlie]

Sorry to have to say it, but this is pretty much exactly how spider mites look. You can usually see them on the undersides of leaves that are turning yellow but they are small and are best viewed with a magnifier of some sort.

The 3-in-1 does not work very well for spider mites, unfortunately. Horticultural oil sprays and baths are somewhat better. Everybody has their own technique but for me the easiest way to "bathe" them is to take a plant outside, turn it on its side, and use a hose to force a hard blast of water against the undersides of the leaves. Then turn the plant 1/4 turn and blast the leaves again, then another quarter turn, blast with water, and a final quarter turn. Then gently lift the wet and heavy bush upright and let it dry before bringing it inside. You usually have to do this 2-3 times in one week to get rid of the mites.

Charlie

[Cherie]

Afraid you'd say that!  I soaked them in the tub last night and let the tree stand in the shower for 15.  I was reading about Horticultural oil sprays, and I'm seeing a few that claim to even kill eggs. Is that even possible?
I can try the hose method but not for much longer

[blupit007]

Cherie,

  Sorry about the mites... I had the same situation as you last year when I had to bring all mine inside. I live in CT so I feel your pain.  Mine all made the trip indoors last week.  I have been gone all week so I don't know how they fared the change.  No reports of ugliness from my mother, so I am assuming they are doing fine. 

  I had spider mites last year also.  I tried a ton of different things, but found one works exceptionally well.  That is the water blasting method that Charlie speaks of.  Just do it in the day time when the temps are above 50, and bring them in as soon as they are dry.  After you can also spray with warm soapy water.  I don't have experience with that part, but know some people who swear by it.  Take a spray bottle, put a small drop of dish detergent in it, then fill with warm water.  Spray the underside, top, and the trunk, everything.  The soap will smother the mites, much like the oil spray you can buy... just another option.
 
  I also have had luck with Bonnie Hort oil spray.  But the soap is safer to spray indoors if need be.

Good luck,
Kristen