Mexican honeysuckle (Justicia spicigera) diagnosis

psuperb1(9 Tucson)May 24, 2010

I have two Justicia spicigera plants (since October 2009). They have been slow to thrive. The plants are sparse and leaves tend to turn black at edges.

Last fall I took some dropped leaves to local cooperative extension and was told to apply some chelated iron to free up nitrogen for plants. I did this about a month ago but the plants still have some black edges on leaves.

Does anyone know if there is anything else I can do to help the plants? Maybe the chelated iron is slow-acting or it will take more than one application.

Thanks for any advice you have to give.

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lazy_gardens

How much sun do they get?
How are you watering them?

    Bookmark   May 24, 2010 at 10:04AM
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psuperb1(9 Tucson)

Lazygardens, one plant in front of house has west exposure, gets full sun this time of year from @10:30 am to sunset. The other is on north side of house and gets full sun this time of year from @9:30 am to 6 pm. (I have no access to east exposure as I rent and that is part of landlady's yard.)

I pour water from plastic gallon (ex-milk) containers into basin around each plant. Five gallons each (@ 1/2 gallon, let soak in, repeat until 5 gallon total) about 8-9 days apart. When we start hitting 100s, I plan to go to 7 days.

What do you think? Thanks.

    Bookmark   May 24, 2010 at 10:37PM
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antm0(Sunset Zone 13)

If I were going to guess at it, I would make sure you aren't using "Softened" water and instead using water straight of the tap.
The burnt tips would lead me to speculate on how well the soil drains, and the frequency of watering could be an issue.

The water should be going to a depth of 18-24 inches.
In the spring, on a plant that has been in the ground at least a year, once every 2 weeks or possibly more should be enough for justicia. Others might disagree :)
In the summer, every 7-12 days should be good.

So my suggestion would be, water deeply but infrequently. (use a hose on slow trickle until you feel or know water has gotten at LEAST 18" down, and any roots that are down there may have strayed and spread outward as well, so make sure you are soaking the "outter skirts" of the plant as well)
Hope it all works out :)
And good luck!

    Bookmark   May 25, 2010 at 9:49PM
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antm0(Sunset Zone 13)

Edit: I misread the date you had planted them, I sorta gave advice on a slightly more established plant. The advice should help a little for now though, I appologize. Also remember, it could possibly explode in growth this fall or next spring. Sometimes things just take a little time to establish ;)

I'd be anxious to hear any other suggestions as well :)

    Bookmark   May 25, 2010 at 11:17PM
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psuperb1(9 Tucson)

Antm0, I waited a little while to reply to see if anyone else had comments. Apparently not. You certainly gave me some points to ponder. I'm hoping your remark "Sometimes things just take a little time to establish" is the case.

I did water yesterday and the watering probe measured in excess of 24". I may cut back to 4 gallons. A possible good sign: A side shoot is popping through about 5-6" from base of plant.

I am not using softened water. I use tap water which is quite hard. I water to drip line and beyond. I tested the drainage before planting. One hole was slower than the other but I thought within accepptable limits.

I can try widening basins a little more and work in (what?) a cactus soil mix to improve drainage. Maybe prune plants close to ground next winter (if they last that long) to get rid of legginess.

My gut says water has too much calcium/chlorine, and the summer sun is too hard on them. Maybe I just don't have hospitable conditions. I'll try a few things then Time will tell.

Thanks for taking time to speculate and type your remarks.

    Bookmark   May 26, 2010 at 5:44PM
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grant_in_arizona(USDA Z9 Scottsdale AZ)

You know, the first thing that came to my mind was that they are getting too much sun, but since I'm not personally growing these I wanted to wait/defer to folks who have actual hands on experience. It seems like the happiest ones I've seen have been in dappled shade to mostly shaded conditions. Just a thought. Let's see what folks who actually grow them think of that as a possibility.

Orange is my favorite color, so I hope these will thrive for you. Keep us posted.

Take care,
Grant

    Bookmark   May 26, 2010 at 7:04PM
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judy_b(AZ zone 9)

I'm trying one again because we saw a very well-grown one and my DH became enamored. I've tried growing them before. We'll see what happens this time. I suspect it's as Grant says, a little too much sun is a little too much for them.

    Bookmark   May 26, 2010 at 8:49PM
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antm0(Sunset Zone 13)

The watering basin seems fine for now, but if it does end up taking and growing bigger, then widen basin as needed.

I wouldn't worry about quality of water. Before adding ammendments, wait and see what happens this next year. When you planted them, did you pack the soil down pretty hard around the root ball? Too much compaction can hinder drainage... Appearing dry on top, but may be pretty damp around the feeder roots down below.

Grant is valid in what he says, they PREFER partial sun, but it is quite possible in full sun, I know this because I have witnessed mature ones in full south exposure. I'll see if I can snag a pic for ya to see, it's quite beautiful :)

    Bookmark   May 27, 2010 at 2:22PM
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psuperb1(9 Tucson)

Antm0, Grant, Judy b, Lazygardens: I really appreciate your posts and helpful advice. I like Justicia spicigera and am going to give the plants copious time to adapt. I have no better locations to offer them.

Antm0, I see your point about packing soil around root ball but I'm on the gentle side in that regard. I'll keep in mind that the feeder root may still be damp although topsoil is dry. Glad you mentioned you know of Js surviving in full southern exposure!

Judy b, good luck with your second try. We can both benefit from all the considerations brought up on this thread.

Grant, the Js orange is nice, especially with the shade of green leaves. By the way, on your What's looking good thread, thanks for info on coral bean plant. That's a vibrant shade of red too.

    Bookmark   May 27, 2010 at 7:37PM
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Dr.Nature

This species requires high humidity so I think your problem is arid Arizona. In southern Florida this species quickly reaches 6' tall or more and flowers throughout the year. It prefers well-drained soil and ample irrigation in the dry season here. Hummingbirds go bonkers of it.

    Bookmark   August 20, 2013 at 9:02AM
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