Planar graph with exclusively real and a non-integral chromatic root

Determine whether there exists a planar graph whose chromatic polynomial has only real roots and at least one non-integral chromatic root.

Background

The paper notes that chordal graphs have only nonnegative integer chromatic roots, while some non-chordal graphs have all integer chromatic roots and some non-planar graphs have exclusively real but non-integral chromatic roots. This motivates asking whether the analogous phenomenon can occur for planar graphs. The problem is explicitly identified as remaining widely open.

References

Is there a planar graph $G$ that has real chromatic roots only and contains non-integral chromatic roots?

Real-rooted flow polynomials have only integer roots  (2608.19780 - Zhang et al., 20 Aug 2026) in Problem 1, Preliminaries