I have a mop top robinia in my garden, anyone any info on how to stop
or control it suckering, am just pulling them out by hand at the
minute. thanks

I have a mop top robinia in my garden, anyone any info on how to stop or
control it suckering,

If you mean Robinia pseudoacacia or a similar species, this is what they do.
The only way to prevent it is to remove the parent tree. For more valuable
trees, like crabapples, there are hormone sprays you can use, but for a cheap
weedy tree it's not worth the trouble.

Iris,
Central NY, Zone 5a, Sunset Zone 40
"If we see light at the end of the tunnel, It's the light of the oncoming
train."
Robert Lowell (1917-1977)

Iris Cohen wrote:

I have a mop top robinia in my garden, anyone any info on how to stop or
control it suckering,

If you mean Robinia pseudoacacia or a similar species, this is what they do.
The only way to prevent it is to remove the parent tree. For more valuable
trees, like crabapples, there are hormone sprays you can use, but for a cheap
weedy tree it's not worth the trouble.

It is unfair to refer to all cultivars of Robinia as cheap and weedy. While the
straight species of R. pseudoacacia can be a problem with brittle wood, prolific
self-seeding and suckering, named cultivars are far superior and offer a valuable
presence in the garden. They are often thornless, do not produce large quantities
of flowers and seeds and smaller statures make them significantly less prone to
wind damage. And judging from the price tags attached to them in nurseries, no
one considers them cheap. In particular are the Mop Top or 'Umbraculifera' the OP
referred to, the highly prized, golden foliaged 'Frisia' and the contorted
'Twisty Babe' or its diminutive sister, 'Lace Lady'. These are all excellent and
attractive additions to the landscape and cannot be considered less valuable than
a common crabapple. Suckering has never been a concern with either my Frisia or
the Twisty Babe, however I have encountered it with the Umbraculifera - simply
remove any suckering as it occurs. It's not a big deal.

pam - gardengal