Umatilla & Wallowa-Whitman National Forests

On arriving in Granite, turn north onto FS Rd 73. After about a dozen miles or so FS Rd 73 turns right (east) and heads up towards Anthony Lakes. One can ascend to the lakes to view nice riparian species around the lakes. The vegetation seems to be a bit more reminiscent of the flora found in the Wallowa Mts. The book "Guide to the Plants of the Wallowa Mountains of Northeastern Oregon" by Georgia Mason (U of O Press) may be handy here.
Alternatively, at the intersection where FS Rd 73 turns east, you can continue north on FS Rd 51. After another mile or so, you will intersect with the Blue Mt. Byway, FS Rd 52.
If you continue north on FS Rd 51, you will quickly come to the headwaters of the Grande Ronde River. Travelling this road, you will pass several penstemons (P. attenuatus, P. confertus, and P. procerus) as well as several lupines (L. burkei, L. leucophyllus var. tenuispicus, & L. sulphureus- yellow) among many other plants before intersecting OR 244 after about an hour or so. OR 244 will take you east to Hilgard and then to LaGrande. Another reccommendation if you have plenty of time (near LaGrande) is to proceed west from Hilgard on Interstate 84 a few miles to the next exit. Proceed west on this old highway which parallels I-84 on its north side until you reach FS Rd 31. Turn right onto FS Rd 31 and proceed northeast on this road about 45 minutes until you reach subalpine, floriferous meadows. Turn right onto "primitive" FS Rd 3120 and proceed several bumpy miles to Indian Rock. This area is one that often has one of the best flower blooms I've seen in Oregon at this time of year. Partial plant lists may be viewed here.
If you wish to head west towards Ukiah to explore the Blue Mt. Scenic Byway, turn west on FS Rd 52. This proceeds through subalpine coniferous forests, some of which was burned in recent years. Penstemons, lupines, and paintbrush may be seen along the route. To the west of Pearson Guard Station, you come across the North Fork John Day Overlook, which is FS Rd 55 on the south side of the road. Park where it is safe and proceed downhill on FS Rd 55 on foot. The area was both burned and clearcut, but offers roadside flowers with especially dogbane, which attracts drifts of butterflies and pollinating insects. I've seen at least 8 or more butterfly species here nectaring on the dogbane.
Proceeding west on FS Rd 52, you eventually reach Ukiah. The Ukiah-Dale State Campground does have some Trillium petiolatum (in flower late May into early June) is several miles south of Ukiah on US Highway 395. Turn north a mile west of Ukiah on US Highway 395 for Pendleton, or continue west on FS RD 53 which heads for Heppner. Search for Lupinus sulphureus, L. burkei, and the diminutive L. lepidus var. cusickii ? along this road between FS Rds 5312 & 21. After leaving the forest, the Blue Mountain Scenic Byway descends alongside Willow Creek to Heppner. Head north to Interstate 84 via State Rd 207. Heppner is about 3 hours or so east of Portland.
Partial Plant Lists for the North Fork of the Malheur River: