My guess is, that this would be under the most pristine conditions. Perfect weather, soil, feeding and watering. I've seen pictures of W.Robusta at 2 years and they were 6 to 8 inches. I'm currently germinating some Mexican fan palms, and hoping they will grow quickly. I am brand new to gardening but believe I've found a new love.

My friend in San Diego calls them "weeds". Her neighborhood association does not allow Mexican Fan palms to be planted. You hit the nail on the head as to why. Their rapid growth to sky dusting heights rapidly puts them out of ladder reach for trimming off dead fronds of " the skirt" as the natural appearance of mature trees because dead fronds seldom drop on their own. The skirts attract pests like rats and pigeons, so in a neighborhood like hers, they must be pruned. also the dead fronts create a fire hazard. Professional tree trimmers that have to use a "cherry picker" truck can cost hundreds of dollars per tree. They are also prolific seeders and little fan palms pop up everywhere birds drop them: "weeds".

I'm sure in Florida where they are not native, they could be considered invasive.

Hi. I moved to Arizona last year into a small desert community. I have been watching the palms here as I was originally from Massachusetts and it is awesome to see palms and other plants growing here. There are many Robusta palms growing here. They don't grow in height very quickly but they grow new leaves at a good pace. I only get about 9" of rain a year here, yet the street palms do not suffer at all. There are a few with huge "skirts" but mostly the winds I have here prune the palms pretty well and the dead leaves hit the ground with a crash. Also most of the Robusta palms in my area have trunks that are free of boot jacks. The shorter, younger palms retain them, but the tall Robustas generally do not. Most Robustas here are blooming right now and the seed ripens in October. In a place like San Diego, I would guess these palms would grow much faster because of the rainfall. I don't know how well Robustas grow in Florida because of the humidity. I would think Palmetto trees would be a better choice for Florida. One thing I should mention as far as a palm being evasive. In the area where I live, the only Robusta seedlings that naturally sprouted I have seen survive were growing under the protection of other plants or objects. I have seen some Date palm seedlings in the open growing well but I can get an evening cold snap that damages some of the palms here and can kill young trees.

They are very dangerous plants

This post was edited by jimhardy on Sun, Jun 16, 13 at 9:16

I seriously doubt too many Washingtonias even grow half that rate, under the best conditions.. and you have to remember that growth rate does NOT include seedling growth, which is significantly slower. 60' palms in So California are usually closer to 20+ years old, not 6. In fact, a 6 year old palm maybe only be 6' tall or MAyBE 10' if all goes perfectly.. .THEN it will start growing pretty fast (but not 6' a year). The 100 year old palms in Santa Monica or maybe 150' tall... not 600'.

You will have no problem keeping it under 5 feet in 3 years, or under 4 feet for that matter. As far as controlling their reproduction, there is no way to do that unless you continuously cut the flower spikes that appear at any time of the year.