Companion plants for Portulaca
Portulaca blooms from June through September. It wants full sun and low water. The 8 companion pairings below each state why the pairing works.
Blooming before Portulaca opens

Rosemary
Shares full sun and low water; blooms in early spring, before this one opens; stands well above at 3.5 ft, a canopy to plant beneath; evergreen, so the bed keeps its shape through winter.

Candytuft
Shares full sun and low water; blooms in mid spring, before this one opens; evergreen, so the bed keeps its shape through winter; its white flowers settle the orange.

Viburnum
Shares full sun and low to moderate water; blooms in mid spring, before this one opens; stands well above at 6.5 ft, a canopy to plant beneath; its white flowers settle the orange.
Taking over as Portulaca finishes

Fountain Grass
Shares full sun and low water; stands well above at 3.5 ft, a canopy to plant beneath; overlaps, then carries the display into mid fall; its seed heads stand through winter, for structure and the birds.

Switchgrass
Shares full sun and low water; stands well above at 5 ft, a canopy to plant beneath; overlaps, then carries the display into mid fall; its seed heads stand through winter, for structure and the birds.
Blooming alongside

False Indigo
Shares full sun and low water; opens in late spring and overlaps into this one's season; stands well above at 3.5 ft, a canopy to plant beneath; its seed heads stand through winter, for structure and the birds.

Little Bluestem
Shares full sun and low water; stands well above at 3.5 ft, a canopy to plant beneath; its seed heads stand through winter, for structure and the birds; blue against orange, for contrast.

Globe Thistle
Shares full sun and low water; stands well above at 3.5 ft, a canopy to plant beneath; its seed heads stand through winter, for structure and the birds; blue against orange, for contrast.