Need some Jacaranda advice - Calling Fast Feet!!!!

[MattyB]

Please, any is welcome to offer up advice, but I really want Ken to take a look at this Jacaranda. Due to the close proximity to my house, and the need to keep the branches off of the siding and the roof (scraping during high winds and roof rats), this Jacaranda is getting more and more unbalanced as it gets larger and larger. I don't mind the look, but I'm wondering if I'm going to be facing some possible structural issues in the future. Are Jacarandas prone to uprooting? Can they break large branches? Take a look and let me know what you think.

[fastfeat]

Matt--

Looks like you've done a pretty good job keeping it away from the house so far. Structurally, it's not bad, but not the strongest either. I don't particularly like the two trunks, but, on the plus side, the lower, leaning one would be more likely to fail at some point. You probably could train the closer trunk to have some canopy over the roof safely, but, of course, you'll still have litter, rats, etc on the roof to deal with. You might want to reduce some of the weight on that lower trunk by reducing some of the width of its spread.

As for roots, there's always a chance of trees uprooting, esp. on shallow soils during periods of heavy rain and/or wind. And especially if the trees have a girdling root(s). If it was a tree from the majority of CA retail nurseries, I'd say odds of a defective root system are good.

For me, bottom line is that it's a gamble. I like gambling, but I don't like losing money. You're probably OK for at least several more years if you manage it correctly (and if you pay your homeowner's insurance...). If I were buying your house and had that Jac there, I wouldn't fear it, but would have to consider the possibility of removing it in the long-term.

Hope that helps...

[MattyB]

Thank you so much Ken for your expert advice. I'll do some selective pruning for the time being, to lessen the weight, and start thinking about how to start phasing in some other canopy option in that general area.

One option I was thinking of was just putting another Jacaranda in about 12 feet further away from the house, basically right where the bananas are. This is where the washer water lets out and probably one of the reasons that this jacaranda is growing so fast.

So what's the deal with CA nursery grown jacarandas having defective roots?

[Xerarch]

Any tree with a woody root system that is container grown has a high susceptibility of getting girdled roots. It's too easy to leave them in a container too long before bumping them up to the next size at the nursery. The roots hit the sides of the container and wind around and around, then they never break the habit after being planted. It can be hard to detect also when buying a tree. If you buy, say, a 15 gallon tree, you can pull it out of the container a bit and see if it is getting girdled, what you can't see is if it is girdled all the way back at the 5 gallon or 1 gallon size. I have seen many many trees fail because of this.

[MattyB]

Hmmmmm, so they don't just absorb and graft together and send out new roots I guess.

So, if I want to buy another Jacaranda, what do I do? Do I have to germinate it and plant it out early?

[DoomsDave]

Matt:

I too recall a lot of problems with root girdling, in which the roots turn into a gordian knot that strangles itself as the roots get bigger. Some trees send out new roots (like Ficus) but many don't.

Look to buy small, but vigorous looking young plants with a lot of foliage on top. Small ones blooming in the pots almost always have some root curling, in my experience.

Sometimes roots can damage a house, but that can be a tricky thing to predict.

Sometimes roots don't grow under a house because no water gets under there. The roots start to grow, but, finding no water, just stop. That's also why trees almost never push up street pavement, but heave sidewalks all over the place. If that's happened in your case, the tree will be lopsided, and might fall over with no roots on the one side to hold it down.

Sometimes roots do grow under your house, and if the tree falls over they can damage the structure as they rip out.

Jacks are great trees, but maybe plant another one in a more central spot.

I haven't noticed that Jacarandas are prone to breakage of the limbs the way, say Fraxinus (Ash) trees or willows are. Those feathery leaves let the wind go through without whipping around all over the place.

Jacks do make great firewood.

[MattyB]

Ok, great advice Dave, thank you.

Oh, one more thing. When the tree was smaller at the base I could see that it had a hardware cloth (1/4" wire mesh) gopher cage that it was planted in. It has since swallowed up that wire cage. This is different than root girdling right? It's ok that the wire mesh is being eaten up by the trunk right?

[Xerarch]

Perhaps someone in your area can recommend a nursery that has good practices for reducing root girdling. I would agree that smaller trees have a better chance of not developing the problem, there are also some limited options for treating the roots that look suspicious at the time of planting. I have had luck just cutting off a few of the likely offenders with hand pruners at the time of planting as long as they are not too big, also just "unwinding" some of the visible ones before you put it in the hole.

[bahia]

Not mentioned so far, but Jacaranda mimosifolia is notoriously weak-wooded, and does break major branches quite often in wind storms. the irregular branching on this species typically results in lots of narrow crotch angles that can be more subject to breaking as well, so look out for this as you prune to establish basic initial tree structure. Also, with larger shrubs and trees I've removed over the years that had originally been planted out with gopher cages typically sized for 5 gallon sized plants, good rooting was almost always lacking and had been impacted by the cages. One of the major reasons I am reluctant to install them so small around things that will eventually get tall and provide a wind sail. I'd suggest planting a new one further out and eventually removing this one is your best bet, and planting from a young one or five gallon size would be better still.