With IPHost Network Monitor you can run simple snmp requests against a HP device in your network.
hpVlanNumber
hp Vlan Number
1.3.6.1.4.1.11.2.14.11.5.1.3.1.1.1
The number of currently defined VLANs in the device. Though VLANs should be created using contiguous VLAN IDs, this is not mandatory. Gaps in the VLAN ID sequence may also result from the deletion of existing VLANs. Therefore, this value represents the total number of VLANs in the device and should not be used to indicate the highest VLAN ID value currently in use.
Back to hpprocurve-v2-hpvlan MIB page.
IPHost Network monitor allows you to monitor hpVlanNumber on Hewlett Packard device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco routers right now.