Hi Anna

Thanks for reaching out for help diagnosing probelems with your crab apple.  We have had a look at the photos of the tree and surrounds, including the weed free gravel surrounding the tree. Our very first concern is the tree may be showing significant symptoms of herbicide damage. Gravel areas such as these are frequently treated with both pre and post-emergent herbicides. In  some circumstances, prememergent hebicide can be taken up by the roots and significant damage and even death of the tree is possible. 

This tree is exhibiting symptoms that could likely be be casued by a pre-emargent hebicide.  And crabapples are know to be suceptible to this kind of damage.  The blue spruce behind the crab appple is also showing signs that may have been caused by herbicide damage.

Post emergent herbicides can also damage tree due to drift.  But this doesnt appear to be case here in either instance.

Could you please confirm if herbicides have been used in the vicinity of this tree?

To rule out other likely causes, can you provide us some information as follows:

Is the tree irrigated? 

If so, how often and how much? 

Has the irrigation schedule changed recently?

Are there any other trees in the vicinity showing similar symptoms? 

Do you have other crab apple tree in your garden or vicinity, and what condition are they in?

Are there any other pome fruit in your area that are showing similar symptoms. this may also include Pear (Pyrus species) and quince (Cydonia) Apple, crabapple (Malus species), and firethorns (Pyracantha species)

If there are has been sprayed with herbicide, it would be wise to plant a tree that is not susceptible to herbicide damage.

We look forward to you response so that we can accurately diagnose the cause.

here is some more information on herbicide injury to trees.

Sincerely

Julian S

Master Gardener