Somehow I was not able to color the text of my horizontal axis. This is what I set for the parameters:
var options = { colors: ['#B20054', '#993D69', '#BD00FF', '#FFFE40', '#CCB814', '#998F3D', '#40B2FF'], timeline: { colorByRowLabel: true, rowLabelStyle: { fontSize: 9, color: '#603913' }, barLabelStyle: { fontSize: 9 } } hAxis: { textStyle:{color: '#FFF'} } };
Screenshot:

Full code:
var container = document.getElementById('timetracking_Dennis'); var chart = new google.visualization.Timeline(container); var dataTable = new google.visualization.DataTable(); dataTable.addColumn({ type: 'string', id: 'Term' }); dataTable.addColumn({ type: 'string', id: 'Name' }); dataTable.addColumn({ type: 'date', id: 'Start' }); dataTable.addColumn({ type: 'date', id: 'End' }); dataTable.addRows([ [ '#5700', 'Vernieuwing wifi-netwerk', new Date(0,0,0,10,16,0), new Date(0,0,0,10,17,0) ], [ '#5704', 'Account Mike Hees', new Date(0,0,0,10,23,0), new Date(0,0,0,10,28,0) ], [ '#5798', 'Laptop Bas van der Beer traag', new Date(0,0,0,10,15,0), new Date(0,0,0,11,14,0) ], [ '#5832', 'Problemen iMac', new Date(0,0,0,11,24,0), new Date(0,0,0,11,25,0) ], [ '#5832', 'Problemen iMac', new Date(0,0,0,11,34,0), new Date(0,0,0,11,35,0) ], [ '#5856', 'Problemen iMac', new Date(0,0,0,17,28,0), new Date(0,0,0,18,0,0) ], [ '#5856', 'Internet Broekseweg', new Date(0,0,0,9,14,0), new Date(0,0,0,9,15,0) ], [ '#5856', 'Internet Broekseweg', new Date(0,0,0,9,0,0), new Date(0,0,0,10,0,0) ], [ '#5856', 'Internet Broekhovenseweg', new Date(0,0,0,16,2,0), new Date(0,0,0,16,12,0) ], [ '#5857', 'gebruiker Abdel issues met opstarten', new Date(0,0,0,11,37,0), new Date(0,0,0,11,38,0) ], [ '#5895', 'Printer uit flexplek halen', new Date(0,0,0,11,9,0), new Date(0,0,0,11,17,0) ] ]); var options = { colors: ['#B20054', '#993D69', '#BD00FF', '#FFFE40', '#CCB814', '#998F3D', '#40B2FF'], timeline: { colorByRowLabel: true, rowLabelStyle: { fontSize: 9, color: '#603913' }, barLabelStyle: { fontSize: 9 } } }; chart.draw(dataTable, options);